This review article intends to report the advances in the production and application of biochar
f... more This review article intends to report the advances in the production and application of biochar from macroalgae and microalgae and its utilization in anaerobic digestion (AD), aiming to achieve zero waste and promote a circular economy. Biochar, a carbon-rich material derived through pyrolysis or gasification, offers environmental and agricultural benefits due to its stability and porosity. By incorporating biochar into AD systems, improved process efficiency, enhanced microbial activity, and nutrient retention can be achieved. An integrated approach on its production and application can minimize biomass disposal impacts, generate renewable energy, and improve the soil and nutrient management. The use of macroalgae and microalgae for biochar production aligns with the sustainability principles, as these resources have high growth rates and there is no direct competition with the arable land. Thus, the focus of this article is to highlight the advances in algal biochar production with emphasis to the factors influencing biochar properties, structure, characterization, mechanism of biochar action, and the impact of biochar addition on AD. It also evaluates the economic and environmental benefits, featuring the role of this approach in achieving a zero-waste paradigm and supporting circular economy development.
Zeolites possess a microporous crystalline structure, a large surface area, and a uniform pore si... more Zeolites possess a microporous crystalline structure, a large surface area, and a uniform pore size. Natural or synthetic zeolites are commonly utilized for adsorbing organic and inorganic compounds from wastewater because of their unique physicochemical properties and cost-effectiveness. The present review work comprehensively revealed the application of zeolites in removing a diverse range of wastewater contaminates, such as dyes, heavy metal ions, and phenolic compounds, within the framework of contemporary research. The present review work offers a summary of the existing literature about the chemical composition of zeolites and their synthesis by different methods. Subsequently, the article provides a wide range of factors to examine the adsorption mechanisms of both inorganic and organic pollutants using natural zeolites and modified zeolites. This review explores the different mechanisms through which zeolites effectively eliminate pollutants from aquatic matrices. Additionally, this review explores that the Langmuir and pseudo-second-order models are the predominant models used in investigating isothermal and kinetic adsorption and also evaluates the research gap on zeolite through scientometric analysis. The prospective efficacy of zeolite materials in future wastewater treatment may be assessed by a comparative analysis of their capacity to adsorb toxic inorganic and organic contaminates from wastewater, with other adsorbents.
Citrus fruits are subjected to various postharvest practices to safeguard them from pathogenic mi... more Citrus fruits are subjected to various postharvest practices to safeguard them from pathogenic microorganisms and preserve their nutritional value as well as flavor. The currently used postharvest practices include different physical, chemical, and biological processes. The most common physical methods encompass diverse methods like treatments with hot water, thermal curing, light exposure, etc, whereas chemical methods include, hot chemical drenches, application of fungicide, antimicrobial peptides, salicylic acid, nitric oxide, sulfur dioxide, ozone, and other gaseous compounds, in addition to 1-methylcyclopropene (1-MCP) treatments. The biological methods include the application of different biocontrol agents to effectively reduce the pathogenic microorganisms. Although all these treatments effectively reduce pathogenic microorganisms, particularly Penicillium species, the information regarding their influence on the carposphere microflora of citrus fruits, including biocontrol agents and beneficial microorganisms remains inadequately explored. Noteworthy, the carpophore of citrus fruits harbors a variety of microbial communities having crucial role in preserving fruit’s natural environment and defending host from postharvest pathogen attack. Therefore, the present review has discussed different physical and chemical treatment practices employed during postharvest storage condition and their influence on the native microflora of citrus carposphere.
To achieve sustainable development goals (SDGs), drinking water and/or wastewater treatment must ... more To achieve sustainable development goals (SDGs), drinking water and/or wastewater treatment must be performed at a minimum cost along with negligible environmental impacts. Traditional approaches, like coagulation, precipitation, ion exchange, and membrane filtration have numerous drawbacks in terms of cost and effectiveness. Recently, the thermochemical conversion of biomasses/lignocellulosic wastes for biochar production and subsequently their application in the remediation of contaminated matrices is gaining attention. Further, the application of machine learning (ML) and artificial intelligence (AI) to optimize the production and application of biochar is a topical topic. Therefore, this review critically explains the optimised production process of biochar and its application in the removal of a diverse range of organic and inorganic contaminants from contaminated water and wastewater. Moreover, the review highlights the progress in organic and inorganic pollutants remediation with biochar, focusing on the significance and benefits of utilizing ML and AI to optimize adsorption variables and biochar feedstock properties. The surface area, porosity, and functional groups of the biochar, the type and quantity of the pollutants and the solution’s pH, temperature, and ionic strength, all influence the adsorption capacity of the biochar. Furthermore, the duration of the biochar’s interaction with the contaminants and the existence of competing ions are significant factors. Utilizing AI and ML proves to be efficient in terms of cost and time, enabling a multidisciplinary approach to eliminate pollutants using biochar. Finally, this review discusses the challenges associated with the application of ML and AI in the treatment of contaminated water and wastewater using biochar and proposed future prospects to make these technologies economically viable and sustainable.
Conventional pest control measures, such as chemical pesticides and nematicides, have limited eff... more Conventional pest control measures, such as chemical pesticides and nematicides, have limited efficacy and raise environmental concerns, necessitating sustainable and eco-friendly alternatives for pest management. Therefore, to find a complementary eco-friendly pesticide/nematicide, this study investigated the role of fly ash (FA) in managing a notorious pest, Meloidogyne javanica and its impact on the growth and physiology of Abelmoschus esculentus. Molecular characterization using SSU and LSU rDNA gene markers confirmed the identity of Indian M. javanica as belonging to the same species. Biotic stress induced by nematode infection was significantly alleviated (P < 0.05) by FA application at a 20% w/v, regulating of ROS accumulation (44.1% reduction in superoxide anions and 39.7% reduction in hydrogen peroxide content) in the host plant. Moreover, FA enhanced antioxidant defence enzymes like superoxide dismutase (46.6%) and catalase (112%) to combat nematode induced ROS. Furthermore, the application of FA at a 20% concentration significantly improved the biomass and biochemical attributes of okra. Fly ash also upregulated the activity of the important osmo-protectant proline (11.5 μmol/g FW) to mitigate nematode stress in host cells. Suppression of disease indices like gall index and reproduction factor, combined with in-vitro experiments, revealed that FA exhibits strong nematode mortality capacity and thus can be used as a sustainable and eco-friendly control agent against root-knot nematodes.
The effectiveness of almond shell-derived biochar (ASB) in immobilizing soil heavy metals (HMs) a... more The effectiveness of almond shell-derived biochar (ASB) in immobilizing soil heavy metals (HMs) and its impact on soil microbial activity and diversity have not been sufficiently studied. Hence, a pot study was carried out to investigate the effectiveness of ASB addition at 2, 4, and 6 % (w/w) on soil biochemical characteristics and the bioavailability of Cd, Cu, Pb, and Zn to tomato (Solanum lycopersicum L.) plants, as compared to the control (contaminated soil without ASB addition). The addition of ASB promoted plant growth (up to two-fold) and restored the damage to the ultrastructure of chloroplast organelles. In addition, ASB mitigated the adverse effects of HMs toxicity by decreasing oxidative damage, regulating the antioxidant system, improving soil physicochemical properties, and enhancing enzymatic activities. At the phylum level, ASB addition enhanced the relative abundance of Actinobacteriota, Acidobacteriota, and Firmicutes while decreasing the relative abundance of Proteobacteria and Bacteroidota. Furthermore, ASB application increased the relative abundance of several fungal taxa (Ascomycota and Mortierellomycota) while reducing the relative abundance of Basidiomycota in the soil. The ASB-induced improvement in soil properties, microbial community, and diversity led to a significant decrease in the DTPA-extractable HMs down to 41.0 %, 51.0 %, 52.0 %, and 35.0 % for Cd, Cu, Pb, and Zn, respectively, as compared to the control. The highest doses of ASB (ASB6) significantly reduced the metals content by 26.0 % for Cd, 78.0 % for Cu, 38.0 % for Pb, and 20.0 % for Zn in the roots, and 72.0 % for Cd, 67.0 % for Cu, 46.0 % for Pb, and 35.0 % for Zn in the shoots, as compared to the control. The structural equation model predicts that soil pH and organic matter are driving factors in reducing the availability and uptake of HMs. ASB could be used as a sustainable trial for remediation of HMs polluted soils and reducing metal content in edible plants.
For environmental sustainability and to achieve sustainable development goals (SDGs), drinking wa... more For environmental sustainability and to achieve sustainable development goals (SDGs), drinking water treatment must be done at a reasonable cost with minimal environmental impact. Therefore, treating contaminated drinking water requires materials and approaches that are inexpensive, produced locally, and effortlessly. Hence, locally available materials and their derivatives, such as biochar (BC) and activated carbon (AC) were investigated thoroughly. Several researchers and their findings show that the application of locally accessible materials and their derivatives are capable of the adsorptive removal of organic and inorganic contaminants from drinking water. The application of locally available materials such as lignocellulosic materials/waste and its thermochemically derived products, including BC and AC were found effective in the treatment of contaminated drinking water. Thus, this review aims to thoroughly examine the latest developments in the use of locally accessible feedstocks for tailoring BC and AC, as well as their features and applications in the treatment of drinking water. We attempted to explain facts related to the potential mechanisms of BC and AC, such as complexation, co-precipitation, electrostatic interaction, and ion exchange to treat water, thereby achieving a risk-free remediation approach to polluted water. Additionally, this research offers guidance on creating efficient household treatment units based on the health risks associated with customized adsorbents and cost-benefit analyses. Lastly, this review work discusses the current obstacles for using locally accessible materials and their thermo-chemically.
Plastic and mixed plastic waste (PW) has received increased worldwide attention owing to its huge... more Plastic and mixed plastic waste (PW) has received increased worldwide attention owing to its huge rate of production, high persistency in the environment, and unsustainable waste management practices. Therefore, sustainable PW management and upcycling approaches are imperative to achieve the objectives of the United Nations Sustainable Development Goals. Numerous recent studies have shown the application and feasibility of various PW conversion techniques to produce materials with better economic value. Within this framework, the current review provides an in-depth analysis of cutting-edge thermochemical technologies such as pyrolysis, gasification, carbonization, and photocatalysis that can be used to value plastic and mixed PW in order to produce energy and industrial chemicals. Additionally, a thorough examination of the environmental impacts of contemporary PW upcycling techniques and their commercial feasibility through life cycle assessment (LCA) and techno-economical assessment are provided in this review. Finally, this review emphasizes the opportunities and challenges accompanying with existing PW upcycling techniques and deliver recommendations for future research works.
Biochar can be used for multifunctional applications including the improvement of soil health and... more Biochar can be used for multifunctional applications including the improvement of soil health and carbon storage, remediation of contaminated soil and water resources, mitigation of greenhouse gas emissions and odorous compounds, and feed supplementation to improve animal health. A healthy soil preserves microbial biodiversity that is effective in supressing plant pathogens and pests, recycling nutrients for plant growth, promoting positive symbiotic associations with plant roots, improving soil structure to supply water and nutrients, and ultimately enhancing soil productivity and plant growth. As a soil amendment, biochar assures soil biological health through different processes. First, biochar supports habitats for microorganisms due to its porous nature and by promoting the formation of stable soil micro-aggregates. Biochar also serves as a carbon and nutrient source. Biochar alters soil physical and chemical properties, creating optimum soil conditions for microbial diversity. Biochar can also immobilize soil pollutants and reduce their bioavailability that would otherwise inhibit microbial growth. However, depending on the pyrolysis settings and feedstock resources, biochar can be comprised of contaminants including polycyclic aromatic hydrocarbons and potentially toxic elements that can inhibit microbial activity, thereby impacting soil health.
Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics... more Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics can be gradually released from microplastics (MPs) into the aquatic environment during their aging and fragmentation because most of them do not chemically react with the polymers. Some are known to be hazardous substances, which can cause toxicity effects on organisms and pose ecological risks. In this paper, the application of functional additives in MPs and their leaching in the environment are first summarized followed by their release mechanisms including photooxidation, chemical oxidation, biochemical degradation, and physical abrasion. Important factors affecting the additive release from MPs are also reviewed. Generally, smaller particle size, light irradiation, high temperature, dissolved organic matter (DOM) existence and alkaline conditions can promote the release of chemicals from MPs. In addition, the release of additives is also influenced by the polymer's structure, electrolyte types, as well as salinity. These additives may transfer into the organisms after ingestion and disrupt various biological processes, leading to developmental malformations and toxicity in offspring. Nonetheless, challenges on the toxicity of chemicals in MPs remain hindering the risk assessment on human health from MPs in the environment. Future research is suggested to strengthen research on the leaching experiment in the actual environment, develop more techniques and analysis methods to identify leaching products, and evaluate the toxicity effects of additives from MPs based on more model organisms. The work gives a comprehensive overview of current process for MP additive release in natural waters, summarizes their toxicity effects on organisms, and provides recommendations for future research.
Degradation of land implies either a provisional or permanent deterioration in its productive pot... more Degradation of land implies either a provisional or permanent deterioration in its productive potential, which has an adverse impact on agriculture, biodiversity, and the environment. Land degradation is common in many nations across the globe and has severe adverse environmental consequences. It has a negative impact on livelihood as it diminishes agricultural land productivity, endangers food security, and raises disease risk. Previous studies have confirmed that various bamboo species have efficient in land restoration programmes due to its growth potential and wide acceptability in socioeconomic benefits. Therefore, present governments are interested in funding bamboo-related land restoration programmes across the globe. In this context, we have made an attempt to review the current state of the art of landscape restoration programmes and the role of bamboo plantations with possible influence on economic, social, and political factors in the Indian scenario. This review highlights various restoration programmes of bamboo with detailed explanations, such as heavily contaminated areas, village drylands, fly ash dumps, mine contaminated soils, deforestation programmes, etc. The present study has discussed various success stories of bamboo plantation programmes and the challenges in its implication. It is estimated that about 30% of India's land area is degraded, and erosion is the primary cause. To control this, bamboo is one of the suitable plants as it has a wide variety of species available as per the local climate of India. Over 30 years, bamboo has played the role of a sustainable crop for land restoration and received massive attention from stakeholders. Furthermore, the study has pointed out site-specific bamboo species and its gene bank information, which could be very helpful in restoration programmes of degraded land in near future.
Anaerobic digestion (AD) of agricultural wastes is a promising approach for energy recovery and c... more Anaerobic digestion (AD) of agricultural wastes is a promising approach for energy recovery and crop residue management. However, its recalcitrant chemical structure hinders microbial hydrolysis and reduces biomethane production under AD. Biochar supplementation has been proven to promote the digestibility and biomethanation of lignocellulosic substrates. Therefore, this study investigated the influence of different pyrolysis temperatures (450 â—¦C, 550 â—¦C, and 650 â—¦C) on the physicochemical properties of biochar. Furthermore, the impact of ruminal content biochar supplementation (1 %, 2 %, and 3 %) on the AD of rice straw with rumen fluid as inoculum has been investigated. The ruminal content biochar (RUCB) supplemented reactors showed an increment in biomethane yield and the highest cumulative biomethane yield 243.11 mL/g volatile solids (VS)) was recorded at 2 % RUCB supplementation, followed by 227.12 mL/g VS at 1 % RUCB supplementation and 162.86 mL/g VS at 3 % RUCB supplementation (P > 0.05). Compared to the control reactors (128.68 mL/g VS), RUCB supplemented reactors exhibited 1.88-fold, 1.76-fold, and 1.26-fold increments in biomethane yield due to pH stabilization and facilitation of microbial biofilm formation on the biochar. The correlation analysis showed that biomethane production is positively correlated with VS reduction (R2 = 0.9852). This study proposed a potential strategy to utilize ruminal content waste as a feedstock for biochar production and its application in AD for accelerating the biomethanation of rice straw.
International Journal of Environmental Science and Technology, 2023
Ecological restoration of fly ash-degraded soils is a major concern for developing countries like... more Ecological restoration of fly ash-degraded soils is a major concern for developing countries like India. So far, various physicochemical techniques have been employed to restore these polluted lands, but the limitations of cost, inefficiency, and secondary pollutant generation have forced ecologists to look for alternative approaches. Phytoremediation has been widely employed to replace these techniques, and to produce an economic asset along with the restoration of fly ash-degraded land, through bamboo species which serve as a parallel factor increasing the overall efficiency of bio methods, becomes very interesting. Four bamboo species, Bambusa balcooa, B. vulgaris 'wamin', B. bambos, and B. vulgaris, were planted at abandoned fly ash dumpsite. After two years of plantation, there was a significant improvement in all the physicochemical characteristics of the fly ash dumpsite. Phytoremediation indices in terms of bioconcentration factor (BCF) (1.26 and 1.72) and translocation factor (TF) (1.98 and 1.25) presented that B. bambos is the ideal species for the phytoextraction of Cr and Zn, while B. balcooa is an ideal species for the phytostabilization of lead (Pb), arsenic (As), and zinc (Zn), B. vulgaris 'wamin' for the phytostabilization of copper (Cu), nickel (Ni), Zn, and As and B. vulgaris for phytostabilization of Cu, chromium (Cr), and Ni, respectively. There was a significant improvement in biomass production in all the bamboo species being highest in B. balcooa (1087 kg ha −1) after two years of establishment on the fly ash dumpsite. Further, B. balcooa was found as the ideal bamboo species for sequestration of atmospheric carbon dioxide (CO 2) (8217 tonnes C ha −1 year −1). This work further suggests that B. balcooa is an excellent species for eco-restoration with a reliable air pollution tolerance index (APTI) (16.65). Principal component analysis demonstrated that B. bambos is the most potent bamboo species for phytoremediation of fly ash dumpsites owing to its high biomass capacity, positively correlated with hyperaccumulation of heavy metals. However, the fate of heavy metals after litter decomposition needs to be examined in detail to make this study a widespread approach. Editorial responsibility: Agnieszka Galuszka.
Microplastics (MPs) as emerging persistent pollutants have been a growing global concern. Althoug... more Microplastics (MPs) as emerging persistent pollutants have been a growing global concern. Although MPs are extensively studied in aquatic systems, their presence and fate in agricultural systems are not fully understood. In the agricultural soils, major causes of MPs pollution include application of biosolids and compost, wastewater irrigation, mulching film, polymer-based fertilizers and pesticides, and atmospheric deposition. The fate and dispersion of MPs in the soil environment are mainly associated with the soil characteristics, cultivation practices, and diversity of soil biota. Although there is emerging pollution of MPs in the soil environment, no standardized detection and quantification techniques are available. This study comprehensively reviews the sources, fate, and dispersion of MPs in the soil environment, discusses the interactions and effects of MPs on soil biota, and highlights the recent advancements in detection and quantification methods of MPs. The prospects for future research include biomagnification potency, cytotoxic effects on human/animals, nonlinear behavior in the soil environment , standardized analytical methods, best management practices, and global policies in the agricultural industry for the sake of sustainable development.
Excessive utilization of synthetic plastics has led to a major detrimental impact on the environm... more Excessive utilization of synthetic plastics has led to a major detrimental impact on the environment. Plastic pollution and accumulation in water bodies have threatened the survival of marine life. Plastic pollution can be prevented by using biopolymers that are eco-friendly and can be naturally produced by certain living organisms. The biopolymers have environmental advantages over synthetic plastics, such as biodegradability and biocompatibility. In comparison to plants and other microbial systems, bacteria can accumulate a high amount of polyhydroxyalkanoates (PHAs). However, the major stumbling block in the production of bacterial PHAs is its low cost-effectiveness due to costs associated with fermentaion and down-stream processing. In consideration with the above properties, opportunities and challeges associated with bacterial PHAs, this review focuses on structural diversity of PHAs, biosynthesis mechanism in bacteria, biodegradation, life cycle analysis, and environmental impact of bioplastic production. It further enumerates the advanced tools and techniques for bacterial PHA production, along with various factors affecting the commercialization of bioplastics. Extraction methods, down-stream processing, and biomedical applications of PHAs are also discussed. The opportunities and challenges in the commercialization of bacterial PHAs along with future scenario and environmental sustainability are presented for the purpose of fostering sustainable development.
Biochar (BC) is a material synthesized from biomass by thermochemical
conversion. Physicochemical... more Biochar (BC) is a material synthesized from biomass by thermochemical conversion. Physicochemical and functional properties of BCs can be enhanced by several methods of activation or functionalization. The activated and functionalized BCs with a large surface area and abundant surface functional groups can serve as effective catalysts or catalyst supports for various chemical transformations as well as for adsorption/sorption/ enrichment of low-concentration pollutant streams. Among them, remediation of environmental contaminants and production of a range of bioproducts in biorefineries have attracted much attention in the context of achieving green and sustainable development. Although the applications of BC as adsorbents in removal of pollutants have been discussed extensively, there is a lot of untapped potential with new applications of BCs as catalysts or catalyst supports for advanced oxidation processes (AOPs) and sustainable biorefineries. In this review, the production and activation/functionalization of BCs are scrutinized. The mechanisms of activated and functionalized BC and BC-supported catalysts in degradation of organic contaminants via AOPs assisted with hydrogen peroxide (H2O2), peroxydisulfate (PDS), and peroxymonosulfate (PMS) are reviewed. Emerging applications of BC as catalyst for production of biodiesel and high-value chemicals, tar removal, bio-syngas reforming, and energy storage and conversion devices are discussed in detail.
The current review explores the potential application of algal biomass for the production of biof... more The current review explores the potential application of algal biomass for the production of biofuels and biobased products. The variety of processes and pathways through which bio-valorization of algal biomass can be performed are described in this review. Various lipid extraction techniques from algal biomass along with transesterification reactions for biodiesel production are briefly discussed. Processes such as the pretreatment and saccharification of algal biomass, fermentation, gasification, pyrolysis, hydrothermal liquefaction, and anaerobic digestion for the production of biohydrogen, bio-oils, biomethane, biochar (BC), and various bio-based products are reviewed in detail. The biorefinery model and its collaborative approach with various processes are highlighted for the production of eco-friendly, sustainable, and cost-effective biofuels and value-added products. The authors also discuss opportunities and challenges related to bio-valorization of algal biomass and use their own perspective regarding the processes involved in production and the feasibility to make algal research a reality for the production of biofuels and bio-based products in a sustainable manner.
To mitigate the rising level of CO 2 , biological method of CO 2 sequestration is one of the effe... more To mitigate the rising level of CO 2 , biological method of CO 2 sequestration is one of the effective methods. Chemolithotrophic microbes are able to fix atmospheric CO 2 and precipitated polymorphic minerals like calcite, vaterite and aragonite. Based on this, bioactive glass was synthesized by sol-gel process using polymorphic calcium carbon-ate mineral precipitated by chemolithotrophic Serratia sp. ISTD04. Characterization of bioactive material and its bioactivity was evaluated by SEM, EDX, FT-IR, XRD, ICP-MS. SEM analysis revealed biomaterial showing more bioactivity due to deposition of smaller particle like appearance throughout the surface. FT-IR analysis of sintered and immersed bioactive material indicated presence of O-Ca-O, O-Si-O and Si-O-Si functional group. The XRD analysis indicated important features similar to melt-derived Na 2 O-containing glass ceramics like formation of crystalline phase Na 2 Ca 2 Si 3 O 9. Further in-vitro study was performed in simulated body fluid (SBF) and on osteosarcoma cell line, confirmed that material and their supernatant did not reflect any cytotoxicity.
The application of pesticides reduces the loss of crops while simultaneously increasing crop prod... more The application of pesticides reduces the loss of crops while simultaneously increasing crop productivity. However, the frequent use of pesticides can cause serious environmental problems due to their high accumulative and persistent nature. Recently, microalgae technology has received considerable success in the efficient treatment of pesticides pollution. In this review, the metabolic mechanisms responsible for the removal of pesticides are summarized based on previous studies. Different methods used to enhance the ability of microalgae to remove pesticides are critically evaluated. The recycling ofmicroalgae biomass afterwastewater treatment for biochar preparation and biodiesel production using the biorefinery approach is also introduced. Furthermore, we present potential future research directions to highlight the prospects of microalgae research in the removal of pesticides along with the production of value-added products.
In the present study, genomic analysis of a previously reported carbon dioxide (Co 2) sequesterin... more In the present study, genomic analysis of a previously reported carbon dioxide (Co 2) sequestering bacterium Serratia sp. ISTD04 was performed along with exopolysaccharide (EPS) production. Genomic analysis identified key and accessory enzymes responsible for CO 2 sequestration. eps synthesis genes were discovered in the genome and identified 8 putative clusters responsible for lipopolysaccharide, stewartan, emulsan, polysaccharide B, capsular polysaccharide and fatty acid-saccharide production. The production of EPS was found to be 0.88 ± 0.08, 1.25 ± 0.13 and 1.44 ± 0.10 g L −1 on glucose, bicarbonate (NaHCo 3) and NaHCo 3 plus glucose respectively at pH 7.8. After optimizing process parameters, the EPS production increased more than 3 folds. The morphology of strain and elemental composition of EPS was characterized by SEM-EDX. The functional groups, monomer composition, linkage analysis and structure of purified EPS was characterized by FTIR, GC-MS and 1 H and 13 C NMR. Glucose, galactose, mannose and glucosamine are the monomers detected in the EPS. EPS was further applied for bioflocculation (kaolin test) and dye removal. The EPS showed 68% ± 0.9 flocculating activity and decolorized cationic dye acridine orange (80%) and crystal violet (95%). The results highlight Co 2 sequestration and eps production potential of Serratia sp. ISTD04 that can be harnessed in future. With the increase in atmospheric carbon dioxide (CO 2) concentration, there is disturbance in global climate equilibrium as a result the global temperature is rising at a continuous pace. This increase in CO 2 emission is mainly due to unchecked anthropogenic activities. So, there is an urgent need to reduce the level of CO 2 emission in the atmosphere from various sources. The emission can be reduced by various physical, chemical and biological processes 1,2. Biological fixation of CO 2 by plants and microorganisms is the most common and effective process for sustainable CO 2 sequestration 2. The microorganism accountable for CO 2 sequestration belongs to archaea (Euryarchaeota and Crenarchaeota) and bacteria (Aquificae, Actinobacteria, Chloroflexi Proteobacteria, Chlorobi, Firmicutes and Thermodesulfobacteria). Microbes can fix CO 2 through six known pathways but the most predominant is Calvin-Benson-Bassham (CBB) pathway 2,3. The microorganism sequesters CO 2 through a carbon concentrating mechanism with the help of well-known enzymes Ribulose-1,5-bisphosphate carboxylase/oxygen-ase (RuBisCO) and carbonic anhydrase 3. These microbes can convert CO 2 into biomass and bioproducts such as lipids, polyhydroxyalkanoates (PHAs), and extracellular polymeric substances (EPSs) 2,4,5. Serratia sp. ISTD04 has been reported for CO 2 sequestration and production of value-added products 1,5. Genus Serratia belongs to Enterobacteriaceae family; they are gram-negative, rod-shaped and facultative anaerobes that dwells in a diverse environment such as water, soil, plants, rhizospheric soil and other organisms 6. Serratia has been reported from diverse site and perform various functions such as Serratia fonticola RB-25 isolated from a waste landfill for quorum sensing, Serratia plymuthica and other strains AS12, AS9, S13 and 4Rx13 are associated with plants or plant-growth-promoting activities, Serratia proteamaculans 568 with a detailed genome analysis on chitinase production, Serratia marcescens WW4 isolated from a paper machine, S. marc-escens FGI 94 associated with leaf-cutter ant fungus garden and S. marcescens Db11 pathogen of drosophila 4,7,8. This genus is also known for production of value-added products such as enzymes, biosurfactants, pigments, fatty acids, flavors and polyhydroxyalkanoates 2,3,9. The genes and pathways responsible for CO 2 sequestration and bioproduct synthesis can be further elucidated by the genomic, transcriptomic and proteomic approach. Identification of genes and enzymes controlling particular process will provide an opportunity to further improve
This review article intends to report the advances in the production and application of biochar
f... more This review article intends to report the advances in the production and application of biochar from macroalgae and microalgae and its utilization in anaerobic digestion (AD), aiming to achieve zero waste and promote a circular economy. Biochar, a carbon-rich material derived through pyrolysis or gasification, offers environmental and agricultural benefits due to its stability and porosity. By incorporating biochar into AD systems, improved process efficiency, enhanced microbial activity, and nutrient retention can be achieved. An integrated approach on its production and application can minimize biomass disposal impacts, generate renewable energy, and improve the soil and nutrient management. The use of macroalgae and microalgae for biochar production aligns with the sustainability principles, as these resources have high growth rates and there is no direct competition with the arable land. Thus, the focus of this article is to highlight the advances in algal biochar production with emphasis to the factors influencing biochar properties, structure, characterization, mechanism of biochar action, and the impact of biochar addition on AD. It also evaluates the economic and environmental benefits, featuring the role of this approach in achieving a zero-waste paradigm and supporting circular economy development.
Zeolites possess a microporous crystalline structure, a large surface area, and a uniform pore si... more Zeolites possess a microporous crystalline structure, a large surface area, and a uniform pore size. Natural or synthetic zeolites are commonly utilized for adsorbing organic and inorganic compounds from wastewater because of their unique physicochemical properties and cost-effectiveness. The present review work comprehensively revealed the application of zeolites in removing a diverse range of wastewater contaminates, such as dyes, heavy metal ions, and phenolic compounds, within the framework of contemporary research. The present review work offers a summary of the existing literature about the chemical composition of zeolites and their synthesis by different methods. Subsequently, the article provides a wide range of factors to examine the adsorption mechanisms of both inorganic and organic pollutants using natural zeolites and modified zeolites. This review explores the different mechanisms through which zeolites effectively eliminate pollutants from aquatic matrices. Additionally, this review explores that the Langmuir and pseudo-second-order models are the predominant models used in investigating isothermal and kinetic adsorption and also evaluates the research gap on zeolite through scientometric analysis. The prospective efficacy of zeolite materials in future wastewater treatment may be assessed by a comparative analysis of their capacity to adsorb toxic inorganic and organic contaminates from wastewater, with other adsorbents.
Citrus fruits are subjected to various postharvest practices to safeguard them from pathogenic mi... more Citrus fruits are subjected to various postharvest practices to safeguard them from pathogenic microorganisms and preserve their nutritional value as well as flavor. The currently used postharvest practices include different physical, chemical, and biological processes. The most common physical methods encompass diverse methods like treatments with hot water, thermal curing, light exposure, etc, whereas chemical methods include, hot chemical drenches, application of fungicide, antimicrobial peptides, salicylic acid, nitric oxide, sulfur dioxide, ozone, and other gaseous compounds, in addition to 1-methylcyclopropene (1-MCP) treatments. The biological methods include the application of different biocontrol agents to effectively reduce the pathogenic microorganisms. Although all these treatments effectively reduce pathogenic microorganisms, particularly Penicillium species, the information regarding their influence on the carposphere microflora of citrus fruits, including biocontrol agents and beneficial microorganisms remains inadequately explored. Noteworthy, the carpophore of citrus fruits harbors a variety of microbial communities having crucial role in preserving fruit’s natural environment and defending host from postharvest pathogen attack. Therefore, the present review has discussed different physical and chemical treatment practices employed during postharvest storage condition and their influence on the native microflora of citrus carposphere.
To achieve sustainable development goals (SDGs), drinking water and/or wastewater treatment must ... more To achieve sustainable development goals (SDGs), drinking water and/or wastewater treatment must be performed at a minimum cost along with negligible environmental impacts. Traditional approaches, like coagulation, precipitation, ion exchange, and membrane filtration have numerous drawbacks in terms of cost and effectiveness. Recently, the thermochemical conversion of biomasses/lignocellulosic wastes for biochar production and subsequently their application in the remediation of contaminated matrices is gaining attention. Further, the application of machine learning (ML) and artificial intelligence (AI) to optimize the production and application of biochar is a topical topic. Therefore, this review critically explains the optimised production process of biochar and its application in the removal of a diverse range of organic and inorganic contaminants from contaminated water and wastewater. Moreover, the review highlights the progress in organic and inorganic pollutants remediation with biochar, focusing on the significance and benefits of utilizing ML and AI to optimize adsorption variables and biochar feedstock properties. The surface area, porosity, and functional groups of the biochar, the type and quantity of the pollutants and the solution’s pH, temperature, and ionic strength, all influence the adsorption capacity of the biochar. Furthermore, the duration of the biochar’s interaction with the contaminants and the existence of competing ions are significant factors. Utilizing AI and ML proves to be efficient in terms of cost and time, enabling a multidisciplinary approach to eliminate pollutants using biochar. Finally, this review discusses the challenges associated with the application of ML and AI in the treatment of contaminated water and wastewater using biochar and proposed future prospects to make these technologies economically viable and sustainable.
Conventional pest control measures, such as chemical pesticides and nematicides, have limited eff... more Conventional pest control measures, such as chemical pesticides and nematicides, have limited efficacy and raise environmental concerns, necessitating sustainable and eco-friendly alternatives for pest management. Therefore, to find a complementary eco-friendly pesticide/nematicide, this study investigated the role of fly ash (FA) in managing a notorious pest, Meloidogyne javanica and its impact on the growth and physiology of Abelmoschus esculentus. Molecular characterization using SSU and LSU rDNA gene markers confirmed the identity of Indian M. javanica as belonging to the same species. Biotic stress induced by nematode infection was significantly alleviated (P < 0.05) by FA application at a 20% w/v, regulating of ROS accumulation (44.1% reduction in superoxide anions and 39.7% reduction in hydrogen peroxide content) in the host plant. Moreover, FA enhanced antioxidant defence enzymes like superoxide dismutase (46.6%) and catalase (112%) to combat nematode induced ROS. Furthermore, the application of FA at a 20% concentration significantly improved the biomass and biochemical attributes of okra. Fly ash also upregulated the activity of the important osmo-protectant proline (11.5 μmol/g FW) to mitigate nematode stress in host cells. Suppression of disease indices like gall index and reproduction factor, combined with in-vitro experiments, revealed that FA exhibits strong nematode mortality capacity and thus can be used as a sustainable and eco-friendly control agent against root-knot nematodes.
The effectiveness of almond shell-derived biochar (ASB) in immobilizing soil heavy metals (HMs) a... more The effectiveness of almond shell-derived biochar (ASB) in immobilizing soil heavy metals (HMs) and its impact on soil microbial activity and diversity have not been sufficiently studied. Hence, a pot study was carried out to investigate the effectiveness of ASB addition at 2, 4, and 6 % (w/w) on soil biochemical characteristics and the bioavailability of Cd, Cu, Pb, and Zn to tomato (Solanum lycopersicum L.) plants, as compared to the control (contaminated soil without ASB addition). The addition of ASB promoted plant growth (up to two-fold) and restored the damage to the ultrastructure of chloroplast organelles. In addition, ASB mitigated the adverse effects of HMs toxicity by decreasing oxidative damage, regulating the antioxidant system, improving soil physicochemical properties, and enhancing enzymatic activities. At the phylum level, ASB addition enhanced the relative abundance of Actinobacteriota, Acidobacteriota, and Firmicutes while decreasing the relative abundance of Proteobacteria and Bacteroidota. Furthermore, ASB application increased the relative abundance of several fungal taxa (Ascomycota and Mortierellomycota) while reducing the relative abundance of Basidiomycota in the soil. The ASB-induced improvement in soil properties, microbial community, and diversity led to a significant decrease in the DTPA-extractable HMs down to 41.0 %, 51.0 %, 52.0 %, and 35.0 % for Cd, Cu, Pb, and Zn, respectively, as compared to the control. The highest doses of ASB (ASB6) significantly reduced the metals content by 26.0 % for Cd, 78.0 % for Cu, 38.0 % for Pb, and 20.0 % for Zn in the roots, and 72.0 % for Cd, 67.0 % for Cu, 46.0 % for Pb, and 35.0 % for Zn in the shoots, as compared to the control. The structural equation model predicts that soil pH and organic matter are driving factors in reducing the availability and uptake of HMs. ASB could be used as a sustainable trial for remediation of HMs polluted soils and reducing metal content in edible plants.
For environmental sustainability and to achieve sustainable development goals (SDGs), drinking wa... more For environmental sustainability and to achieve sustainable development goals (SDGs), drinking water treatment must be done at a reasonable cost with minimal environmental impact. Therefore, treating contaminated drinking water requires materials and approaches that are inexpensive, produced locally, and effortlessly. Hence, locally available materials and their derivatives, such as biochar (BC) and activated carbon (AC) were investigated thoroughly. Several researchers and their findings show that the application of locally accessible materials and their derivatives are capable of the adsorptive removal of organic and inorganic contaminants from drinking water. The application of locally available materials such as lignocellulosic materials/waste and its thermochemically derived products, including BC and AC were found effective in the treatment of contaminated drinking water. Thus, this review aims to thoroughly examine the latest developments in the use of locally accessible feedstocks for tailoring BC and AC, as well as their features and applications in the treatment of drinking water. We attempted to explain facts related to the potential mechanisms of BC and AC, such as complexation, co-precipitation, electrostatic interaction, and ion exchange to treat water, thereby achieving a risk-free remediation approach to polluted water. Additionally, this research offers guidance on creating efficient household treatment units based on the health risks associated with customized adsorbents and cost-benefit analyses. Lastly, this review work discusses the current obstacles for using locally accessible materials and their thermo-chemically.
Plastic and mixed plastic waste (PW) has received increased worldwide attention owing to its huge... more Plastic and mixed plastic waste (PW) has received increased worldwide attention owing to its huge rate of production, high persistency in the environment, and unsustainable waste management practices. Therefore, sustainable PW management and upcycling approaches are imperative to achieve the objectives of the United Nations Sustainable Development Goals. Numerous recent studies have shown the application and feasibility of various PW conversion techniques to produce materials with better economic value. Within this framework, the current review provides an in-depth analysis of cutting-edge thermochemical technologies such as pyrolysis, gasification, carbonization, and photocatalysis that can be used to value plastic and mixed PW in order to produce energy and industrial chemicals. Additionally, a thorough examination of the environmental impacts of contemporary PW upcycling techniques and their commercial feasibility through life cycle assessment (LCA) and techno-economical assessment are provided in this review. Finally, this review emphasizes the opportunities and challenges accompanying with existing PW upcycling techniques and deliver recommendations for future research works.
Biochar can be used for multifunctional applications including the improvement of soil health and... more Biochar can be used for multifunctional applications including the improvement of soil health and carbon storage, remediation of contaminated soil and water resources, mitigation of greenhouse gas emissions and odorous compounds, and feed supplementation to improve animal health. A healthy soil preserves microbial biodiversity that is effective in supressing plant pathogens and pests, recycling nutrients for plant growth, promoting positive symbiotic associations with plant roots, improving soil structure to supply water and nutrients, and ultimately enhancing soil productivity and plant growth. As a soil amendment, biochar assures soil biological health through different processes. First, biochar supports habitats for microorganisms due to its porous nature and by promoting the formation of stable soil micro-aggregates. Biochar also serves as a carbon and nutrient source. Biochar alters soil physical and chemical properties, creating optimum soil conditions for microbial diversity. Biochar can also immobilize soil pollutants and reduce their bioavailability that would otherwise inhibit microbial growth. However, depending on the pyrolysis settings and feedstock resources, biochar can be comprised of contaminants including polycyclic aromatic hydrocarbons and potentially toxic elements that can inhibit microbial activity, thereby impacting soil health.
Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics... more Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics can be gradually released from microplastics (MPs) into the aquatic environment during their aging and fragmentation because most of them do not chemically react with the polymers. Some are known to be hazardous substances, which can cause toxicity effects on organisms and pose ecological risks. In this paper, the application of functional additives in MPs and their leaching in the environment are first summarized followed by their release mechanisms including photooxidation, chemical oxidation, biochemical degradation, and physical abrasion. Important factors affecting the additive release from MPs are also reviewed. Generally, smaller particle size, light irradiation, high temperature, dissolved organic matter (DOM) existence and alkaline conditions can promote the release of chemicals from MPs. In addition, the release of additives is also influenced by the polymer's structure, electrolyte types, as well as salinity. These additives may transfer into the organisms after ingestion and disrupt various biological processes, leading to developmental malformations and toxicity in offspring. Nonetheless, challenges on the toxicity of chemicals in MPs remain hindering the risk assessment on human health from MPs in the environment. Future research is suggested to strengthen research on the leaching experiment in the actual environment, develop more techniques and analysis methods to identify leaching products, and evaluate the toxicity effects of additives from MPs based on more model organisms. The work gives a comprehensive overview of current process for MP additive release in natural waters, summarizes their toxicity effects on organisms, and provides recommendations for future research.
Degradation of land implies either a provisional or permanent deterioration in its productive pot... more Degradation of land implies either a provisional or permanent deterioration in its productive potential, which has an adverse impact on agriculture, biodiversity, and the environment. Land degradation is common in many nations across the globe and has severe adverse environmental consequences. It has a negative impact on livelihood as it diminishes agricultural land productivity, endangers food security, and raises disease risk. Previous studies have confirmed that various bamboo species have efficient in land restoration programmes due to its growth potential and wide acceptability in socioeconomic benefits. Therefore, present governments are interested in funding bamboo-related land restoration programmes across the globe. In this context, we have made an attempt to review the current state of the art of landscape restoration programmes and the role of bamboo plantations with possible influence on economic, social, and political factors in the Indian scenario. This review highlights various restoration programmes of bamboo with detailed explanations, such as heavily contaminated areas, village drylands, fly ash dumps, mine contaminated soils, deforestation programmes, etc. The present study has discussed various success stories of bamboo plantation programmes and the challenges in its implication. It is estimated that about 30% of India's land area is degraded, and erosion is the primary cause. To control this, bamboo is one of the suitable plants as it has a wide variety of species available as per the local climate of India. Over 30 years, bamboo has played the role of a sustainable crop for land restoration and received massive attention from stakeholders. Furthermore, the study has pointed out site-specific bamboo species and its gene bank information, which could be very helpful in restoration programmes of degraded land in near future.
Anaerobic digestion (AD) of agricultural wastes is a promising approach for energy recovery and c... more Anaerobic digestion (AD) of agricultural wastes is a promising approach for energy recovery and crop residue management. However, its recalcitrant chemical structure hinders microbial hydrolysis and reduces biomethane production under AD. Biochar supplementation has been proven to promote the digestibility and biomethanation of lignocellulosic substrates. Therefore, this study investigated the influence of different pyrolysis temperatures (450 â—¦C, 550 â—¦C, and 650 â—¦C) on the physicochemical properties of biochar. Furthermore, the impact of ruminal content biochar supplementation (1 %, 2 %, and 3 %) on the AD of rice straw with rumen fluid as inoculum has been investigated. The ruminal content biochar (RUCB) supplemented reactors showed an increment in biomethane yield and the highest cumulative biomethane yield 243.11 mL/g volatile solids (VS)) was recorded at 2 % RUCB supplementation, followed by 227.12 mL/g VS at 1 % RUCB supplementation and 162.86 mL/g VS at 3 % RUCB supplementation (P > 0.05). Compared to the control reactors (128.68 mL/g VS), RUCB supplemented reactors exhibited 1.88-fold, 1.76-fold, and 1.26-fold increments in biomethane yield due to pH stabilization and facilitation of microbial biofilm formation on the biochar. The correlation analysis showed that biomethane production is positively correlated with VS reduction (R2 = 0.9852). This study proposed a potential strategy to utilize ruminal content waste as a feedstock for biochar production and its application in AD for accelerating the biomethanation of rice straw.
International Journal of Environmental Science and Technology, 2023
Ecological restoration of fly ash-degraded soils is a major concern for developing countries like... more Ecological restoration of fly ash-degraded soils is a major concern for developing countries like India. So far, various physicochemical techniques have been employed to restore these polluted lands, but the limitations of cost, inefficiency, and secondary pollutant generation have forced ecologists to look for alternative approaches. Phytoremediation has been widely employed to replace these techniques, and to produce an economic asset along with the restoration of fly ash-degraded land, through bamboo species which serve as a parallel factor increasing the overall efficiency of bio methods, becomes very interesting. Four bamboo species, Bambusa balcooa, B. vulgaris 'wamin', B. bambos, and B. vulgaris, were planted at abandoned fly ash dumpsite. After two years of plantation, there was a significant improvement in all the physicochemical characteristics of the fly ash dumpsite. Phytoremediation indices in terms of bioconcentration factor (BCF) (1.26 and 1.72) and translocation factor (TF) (1.98 and 1.25) presented that B. bambos is the ideal species for the phytoextraction of Cr and Zn, while B. balcooa is an ideal species for the phytostabilization of lead (Pb), arsenic (As), and zinc (Zn), B. vulgaris 'wamin' for the phytostabilization of copper (Cu), nickel (Ni), Zn, and As and B. vulgaris for phytostabilization of Cu, chromium (Cr), and Ni, respectively. There was a significant improvement in biomass production in all the bamboo species being highest in B. balcooa (1087 kg ha −1) after two years of establishment on the fly ash dumpsite. Further, B. balcooa was found as the ideal bamboo species for sequestration of atmospheric carbon dioxide (CO 2) (8217 tonnes C ha −1 year −1). This work further suggests that B. balcooa is an excellent species for eco-restoration with a reliable air pollution tolerance index (APTI) (16.65). Principal component analysis demonstrated that B. bambos is the most potent bamboo species for phytoremediation of fly ash dumpsites owing to its high biomass capacity, positively correlated with hyperaccumulation of heavy metals. However, the fate of heavy metals after litter decomposition needs to be examined in detail to make this study a widespread approach. Editorial responsibility: Agnieszka Galuszka.
Microplastics (MPs) as emerging persistent pollutants have been a growing global concern. Althoug... more Microplastics (MPs) as emerging persistent pollutants have been a growing global concern. Although MPs are extensively studied in aquatic systems, their presence and fate in agricultural systems are not fully understood. In the agricultural soils, major causes of MPs pollution include application of biosolids and compost, wastewater irrigation, mulching film, polymer-based fertilizers and pesticides, and atmospheric deposition. The fate and dispersion of MPs in the soil environment are mainly associated with the soil characteristics, cultivation practices, and diversity of soil biota. Although there is emerging pollution of MPs in the soil environment, no standardized detection and quantification techniques are available. This study comprehensively reviews the sources, fate, and dispersion of MPs in the soil environment, discusses the interactions and effects of MPs on soil biota, and highlights the recent advancements in detection and quantification methods of MPs. The prospects for future research include biomagnification potency, cytotoxic effects on human/animals, nonlinear behavior in the soil environment , standardized analytical methods, best management practices, and global policies in the agricultural industry for the sake of sustainable development.
Excessive utilization of synthetic plastics has led to a major detrimental impact on the environm... more Excessive utilization of synthetic plastics has led to a major detrimental impact on the environment. Plastic pollution and accumulation in water bodies have threatened the survival of marine life. Plastic pollution can be prevented by using biopolymers that are eco-friendly and can be naturally produced by certain living organisms. The biopolymers have environmental advantages over synthetic plastics, such as biodegradability and biocompatibility. In comparison to plants and other microbial systems, bacteria can accumulate a high amount of polyhydroxyalkanoates (PHAs). However, the major stumbling block in the production of bacterial PHAs is its low cost-effectiveness due to costs associated with fermentaion and down-stream processing. In consideration with the above properties, opportunities and challeges associated with bacterial PHAs, this review focuses on structural diversity of PHAs, biosynthesis mechanism in bacteria, biodegradation, life cycle analysis, and environmental impact of bioplastic production. It further enumerates the advanced tools and techniques for bacterial PHA production, along with various factors affecting the commercialization of bioplastics. Extraction methods, down-stream processing, and biomedical applications of PHAs are also discussed. The opportunities and challenges in the commercialization of bacterial PHAs along with future scenario and environmental sustainability are presented for the purpose of fostering sustainable development.
Biochar (BC) is a material synthesized from biomass by thermochemical
conversion. Physicochemical... more Biochar (BC) is a material synthesized from biomass by thermochemical conversion. Physicochemical and functional properties of BCs can be enhanced by several methods of activation or functionalization. The activated and functionalized BCs with a large surface area and abundant surface functional groups can serve as effective catalysts or catalyst supports for various chemical transformations as well as for adsorption/sorption/ enrichment of low-concentration pollutant streams. Among them, remediation of environmental contaminants and production of a range of bioproducts in biorefineries have attracted much attention in the context of achieving green and sustainable development. Although the applications of BC as adsorbents in removal of pollutants have been discussed extensively, there is a lot of untapped potential with new applications of BCs as catalysts or catalyst supports for advanced oxidation processes (AOPs) and sustainable biorefineries. In this review, the production and activation/functionalization of BCs are scrutinized. The mechanisms of activated and functionalized BC and BC-supported catalysts in degradation of organic contaminants via AOPs assisted with hydrogen peroxide (H2O2), peroxydisulfate (PDS), and peroxymonosulfate (PMS) are reviewed. Emerging applications of BC as catalyst for production of biodiesel and high-value chemicals, tar removal, bio-syngas reforming, and energy storage and conversion devices are discussed in detail.
The current review explores the potential application of algal biomass for the production of biof... more The current review explores the potential application of algal biomass for the production of biofuels and biobased products. The variety of processes and pathways through which bio-valorization of algal biomass can be performed are described in this review. Various lipid extraction techniques from algal biomass along with transesterification reactions for biodiesel production are briefly discussed. Processes such as the pretreatment and saccharification of algal biomass, fermentation, gasification, pyrolysis, hydrothermal liquefaction, and anaerobic digestion for the production of biohydrogen, bio-oils, biomethane, biochar (BC), and various bio-based products are reviewed in detail. The biorefinery model and its collaborative approach with various processes are highlighted for the production of eco-friendly, sustainable, and cost-effective biofuels and value-added products. The authors also discuss opportunities and challenges related to bio-valorization of algal biomass and use their own perspective regarding the processes involved in production and the feasibility to make algal research a reality for the production of biofuels and bio-based products in a sustainable manner.
To mitigate the rising level of CO 2 , biological method of CO 2 sequestration is one of the effe... more To mitigate the rising level of CO 2 , biological method of CO 2 sequestration is one of the effective methods. Chemolithotrophic microbes are able to fix atmospheric CO 2 and precipitated polymorphic minerals like calcite, vaterite and aragonite. Based on this, bioactive glass was synthesized by sol-gel process using polymorphic calcium carbon-ate mineral precipitated by chemolithotrophic Serratia sp. ISTD04. Characterization of bioactive material and its bioactivity was evaluated by SEM, EDX, FT-IR, XRD, ICP-MS. SEM analysis revealed biomaterial showing more bioactivity due to deposition of smaller particle like appearance throughout the surface. FT-IR analysis of sintered and immersed bioactive material indicated presence of O-Ca-O, O-Si-O and Si-O-Si functional group. The XRD analysis indicated important features similar to melt-derived Na 2 O-containing glass ceramics like formation of crystalline phase Na 2 Ca 2 Si 3 O 9. Further in-vitro study was performed in simulated body fluid (SBF) and on osteosarcoma cell line, confirmed that material and their supernatant did not reflect any cytotoxicity.
The application of pesticides reduces the loss of crops while simultaneously increasing crop prod... more The application of pesticides reduces the loss of crops while simultaneously increasing crop productivity. However, the frequent use of pesticides can cause serious environmental problems due to their high accumulative and persistent nature. Recently, microalgae technology has received considerable success in the efficient treatment of pesticides pollution. In this review, the metabolic mechanisms responsible for the removal of pesticides are summarized based on previous studies. Different methods used to enhance the ability of microalgae to remove pesticides are critically evaluated. The recycling ofmicroalgae biomass afterwastewater treatment for biochar preparation and biodiesel production using the biorefinery approach is also introduced. Furthermore, we present potential future research directions to highlight the prospects of microalgae research in the removal of pesticides along with the production of value-added products.
In the present study, genomic analysis of a previously reported carbon dioxide (Co 2) sequesterin... more In the present study, genomic analysis of a previously reported carbon dioxide (Co 2) sequestering bacterium Serratia sp. ISTD04 was performed along with exopolysaccharide (EPS) production. Genomic analysis identified key and accessory enzymes responsible for CO 2 sequestration. eps synthesis genes were discovered in the genome and identified 8 putative clusters responsible for lipopolysaccharide, stewartan, emulsan, polysaccharide B, capsular polysaccharide and fatty acid-saccharide production. The production of EPS was found to be 0.88 ± 0.08, 1.25 ± 0.13 and 1.44 ± 0.10 g L −1 on glucose, bicarbonate (NaHCo 3) and NaHCo 3 plus glucose respectively at pH 7.8. After optimizing process parameters, the EPS production increased more than 3 folds. The morphology of strain and elemental composition of EPS was characterized by SEM-EDX. The functional groups, monomer composition, linkage analysis and structure of purified EPS was characterized by FTIR, GC-MS and 1 H and 13 C NMR. Glucose, galactose, mannose and glucosamine are the monomers detected in the EPS. EPS was further applied for bioflocculation (kaolin test) and dye removal. The EPS showed 68% ± 0.9 flocculating activity and decolorized cationic dye acridine orange (80%) and crystal violet (95%). The results highlight Co 2 sequestration and eps production potential of Serratia sp. ISTD04 that can be harnessed in future. With the increase in atmospheric carbon dioxide (CO 2) concentration, there is disturbance in global climate equilibrium as a result the global temperature is rising at a continuous pace. This increase in CO 2 emission is mainly due to unchecked anthropogenic activities. So, there is an urgent need to reduce the level of CO 2 emission in the atmosphere from various sources. The emission can be reduced by various physical, chemical and biological processes 1,2. Biological fixation of CO 2 by plants and microorganisms is the most common and effective process for sustainable CO 2 sequestration 2. The microorganism accountable for CO 2 sequestration belongs to archaea (Euryarchaeota and Crenarchaeota) and bacteria (Aquificae, Actinobacteria, Chloroflexi Proteobacteria, Chlorobi, Firmicutes and Thermodesulfobacteria). Microbes can fix CO 2 through six known pathways but the most predominant is Calvin-Benson-Bassham (CBB) pathway 2,3. The microorganism sequesters CO 2 through a carbon concentrating mechanism with the help of well-known enzymes Ribulose-1,5-bisphosphate carboxylase/oxygen-ase (RuBisCO) and carbonic anhydrase 3. These microbes can convert CO 2 into biomass and bioproducts such as lipids, polyhydroxyalkanoates (PHAs), and extracellular polymeric substances (EPSs) 2,4,5. Serratia sp. ISTD04 has been reported for CO 2 sequestration and production of value-added products 1,5. Genus Serratia belongs to Enterobacteriaceae family; they are gram-negative, rod-shaped and facultative anaerobes that dwells in a diverse environment such as water, soil, plants, rhizospheric soil and other organisms 6. Serratia has been reported from diverse site and perform various functions such as Serratia fonticola RB-25 isolated from a waste landfill for quorum sensing, Serratia plymuthica and other strains AS12, AS9, S13 and 4Rx13 are associated with plants or plant-growth-promoting activities, Serratia proteamaculans 568 with a detailed genome analysis on chitinase production, Serratia marcescens WW4 isolated from a paper machine, S. marc-escens FGI 94 associated with leaf-cutter ant fungus garden and S. marcescens Db11 pathogen of drosophila 4,7,8. This genus is also known for production of value-added products such as enzymes, biosurfactants, pigments, fatty acids, flavors and polyhydroxyalkanoates 2,3,9. The genes and pathways responsible for CO 2 sequestration and bioproduct synthesis can be further elucidated by the genomic, transcriptomic and proteomic approach. Identification of genes and enzymes controlling particular process will provide an opportunity to further improve
To remediate pesticides from natural environments, various physical, chemical, and biological app... more To remediate pesticides from natural environments, various physical, chemical, and biological approaches have been designed. Nevertheless, each technology has their own pros and cons and their application depends on the level of pollutants, environmental conditions, economics etc. Based on the above discussion, the intend of this book chapter is to provide a comprehensive picture of pesticides pollution in fresh water, staring with their various sources. This chapter also included the health impacts of pesticides, on living organisms including human, their extraction, and characterization techniques along with various remediation approaches. Finally, this chapter provided research gap/challenge associated with pesticides pollution and their remediation approaches and prospect for the future research.
Biochar is a thermo-chemically synthesized/fabricated product of biomass. Recently, biochar appli... more Biochar is a thermo-chemically synthesized/fabricated product of biomass. Recently, biochar applications have spanned into various disciplines such as environmental remediation, water purification, catalysis, tissue engineering, additive in organic waste compost, electrode material and modifier, etc. Modification of biochar is done for specific applications. It brings out the activation of the raw biochar through physical and chemical treatments. Physical modification is frequently done to achieve the superior quality of biochar. In recent years, the application of physical modification method has gained attention as a cost-effective and greener method. The current chapter comprehensively describes the recent developments in physical treatment processes of biochar, opportunities, challenges along with future prospects.
The consumption of energy around the globe is increasing continuously, which is mostly fulfilled ... more The consumption of energy around the globe is increasing continuously, which is mostly fulfilled by fossil fuel which is a nonrenewable source of energy. To meet the demand and supply, researchers need to identify and promote a renewable source of energy. Among various source of renewable energy, microalgae would be considered as an emerging and reliable feedstock which would be able to replace the fossil fuel-based source. Due to its high lipid contents (%30% of dry cell mass) and high growth rate, microalgae would be able to produce higher amount of bioenergy in comparison to various renewable energy sources. Still, the key challenges associated with algal biodiesel are recovery of lipids from algal biomass and their conversion to fatty acid methyl esters (FAME). Therefore, the current chapter enlightens the whole process of biodiesel production including selection of feedstock, harvesting of algal biomass, extraction and purification of lipids, and finally production of biodiesel and value-added products via various routes.
Water, air, and soil pollution are becoming a major concern of the entire world due to rapid indu... more Water, air, and soil pollution are becoming a major concern of the entire world due to rapid industrialization, economic growth, urbanization, increase in population, unsuitable and nonaffordable treatment technologies, and inadequate waste management practices. The safe disposal of solid waste mismanagement is a global issue in terms of environmental contamination and economic sustainability, which requires integrated assessments and holistic approaches for its solution. Landfills remain the main method of solid waste disposal and management in developed and developing countries. However, the major environmental challenges associated with the sustainable management of landfills are the surface and groundwater contamination and greenhouse gases and odor emissions. Phytocapping is an eco-friendly, cost-effective, and sustainable techniques to cover old landfill/dumpsites and to cap new landfills, with an objective to minimize leachate generation by reducing water infiltration into waste and to mitigate greenhouse emission and odor. The present chapter provides an overview of the role and mechanism of phytocapping technology for environmental cleanup.
In view of the wider frame of sustainability transitions in energy, it has opened up the avenues ... more In view of the wider frame of sustainability transitions in energy, it has opened up the avenues to explore resource-efficient as well as low carbon-emitting alternatives to fulfill our energy needs. The solution is sought to enhance energy production and reducing and preventing environmental pollutants from further degradation of the ecology. At present, the application of phytoremediation is explored as both a solution to decontaminate polluted environment and means to generate resource for energy production from biomass. However, the implications for growing energy crops with a phytoremediation potential is yet to be reviewed comprehensively and critically. The chapter attempts to juxtapose the implications in terms of opportunities and challenges about phytoremediation coupled energy production by reviewing the number of relevant research papers. The conclusion of the chapter would bring up inferences concerning social, economic, and environmental aspects with the application of phytoremediation using energy crops.
Increasing population load and an altered lifestyle attitude are exerting extra pressure
on the p... more Increasing population load and an altered lifestyle attitude are exerting extra pressure on the production market, to satisfy the demands and desire of society. The recently developed production and consumption models largely rely on fossil-based resources, which are affecting the environment and natural resources adversely. The cost-effective production of biological materials is an emerging sector with remarkable future prospects and provides many business opportunities. With time the research endeavors are gradually shifting toward bacterial lipids-derived biofuel production, which is more suitable and compatible for an industrial application. The major challenge in the overall process of the production of lipids-derived fuels from microbes is the involved carbon source as it contributes to more than half of the production cost. Therefore the production of lipids and biodiesel from bacteria using different waste materials as carbon source involving the application of advanced biotechnological tools, and modified transesterification reactions will make the biodiesel production cost effective.
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Papers by Dr Manish Kumar
from macroalgae and microalgae and its utilization in anaerobic digestion (AD), aiming to achieve
zero waste and promote a circular economy. Biochar, a carbon-rich material derived through
pyrolysis or gasification, offers environmental and agricultural benefits due to its stability and
porosity. By incorporating biochar into AD systems, improved process efficiency, enhanced microbial
activity, and nutrient retention can be achieved. An integrated approach on its production
and application can minimize biomass disposal impacts, generate renewable energy, and improve
the soil and nutrient management. The use of macroalgae and microalgae for biochar production
aligns with the sustainability principles, as these resources have high growth rates and there is no
direct competition with the arable land. Thus, the focus of this article is to highlight the advances
in algal biochar production with emphasis to the factors influencing biochar properties, structure,
characterization, mechanism of biochar action, and the impact of biochar addition on AD. It also
evaluates the economic and environmental benefits, featuring the role of this approach in
achieving a zero-waste paradigm and supporting circular economy development.
and preserve their nutritional value as well as flavor. The currently used postharvest practices include different
physical, chemical, and biological processes. The most common physical methods encompass diverse methods
like treatments with hot water, thermal curing, light exposure, etc, whereas chemical methods include, hot
chemical drenches, application of fungicide, antimicrobial peptides, salicylic acid, nitric oxide, sulfur dioxide,
ozone, and other gaseous compounds, in addition to 1-methylcyclopropene (1-MCP) treatments. The biological
methods include the application of different biocontrol agents to effectively reduce the pathogenic
microorganisms.
Although all these treatments effectively reduce pathogenic microorganisms, particularly Penicillium species,
the information regarding their influence on the carposphere microflora of citrus fruits, including biocontrol
agents and beneficial microorganisms remains inadequately explored. Noteworthy, the carpophore of citrus
fruits harbors a variety of microbial communities having crucial role in preserving fruit’s natural environment
and defending host from postharvest pathogen attack. Therefore, the present review has discussed different
physical and chemical treatment practices employed during postharvest storage condition and their influence on
the native microflora of citrus carposphere.
environmental concerns, necessitating sustainable and eco-friendly alternatives for pest management. Therefore,
to find a complementary eco-friendly pesticide/nematicide, this study investigated the role of fly ash (FA) in
managing a notorious pest, Meloidogyne javanica and its impact on the growth and physiology of Abelmoschus
esculentus. Molecular characterization using SSU and LSU rDNA gene markers confirmed the identity of Indian
M. javanica as belonging to the same species. Biotic stress induced by nematode infection was significantly alleviated (P < 0.05) by FA application at a 20% w/v, regulating of ROS accumulation (44.1% reduction in
superoxide anions and 39.7% reduction in hydrogen peroxide content) in the host plant. Moreover, FA enhanced
antioxidant defence enzymes like superoxide dismutase (46.6%) and catalase (112%) to combat nematode
induced ROS. Furthermore, the application of FA at a 20% concentration significantly improved the biomass and
biochemical attributes of okra. Fly ash also upregulated the activity of the important osmo-protectant proline
(11.5 μmol/g FW) to mitigate nematode stress in host cells. Suppression of disease indices like gall index and
reproduction factor, combined with in-vitro experiments, revealed that FA exhibits strong nematode mortality
capacity and thus can be used as a sustainable and eco-friendly control agent against root-knot nematodes.
on soil microbial activity and diversity have not been sufficiently studied. Hence, a pot study was carried out to
investigate the effectiveness of ASB addition at 2, 4, and 6 % (w/w) on soil biochemical characteristics and the
bioavailability of Cd, Cu, Pb, and Zn to tomato (Solanum lycopersicum L.) plants, as compared to the control
(contaminated soil without ASB addition). The addition of ASB promoted plant growth (up to two-fold) and
restored the damage to the ultrastructure of chloroplast organelles. In addition, ASB mitigated the adverse effects
of HMs toxicity by decreasing oxidative damage, regulating the antioxidant system, improving soil physicochemical
properties, and enhancing enzymatic activities. At the phylum level, ASB addition enhanced the
relative abundance of Actinobacteriota, Acidobacteriota, and Firmicutes while decreasing the relative abundance of
Proteobacteria and Bacteroidota. Furthermore, ASB application increased the relative abundance of several fungal
taxa (Ascomycota and Mortierellomycota) while reducing the relative abundance of Basidiomycota in the soil. The
ASB-induced improvement in soil properties, microbial community, and diversity led to a significant decrease in
the DTPA-extractable HMs down to 41.0 %, 51.0 %, 52.0 %, and 35.0 % for Cd, Cu, Pb, and Zn, respectively, as
compared to the control. The highest doses of ASB (ASB6) significantly reduced the metals content by 26.0 % for
Cd, 78.0 % for Cu, 38.0 % for Pb, and 20.0 % for Zn in the roots, and 72.0 % for Cd, 67.0 % for Cu, 46.0 % for Pb,
and 35.0 % for Zn in the shoots, as compared to the control. The structural equation model predicts that soil pH
and organic matter are driving factors in reducing the availability and uptake of HMs. ASB could be used as a
sustainable trial for remediation of HMs polluted soils and reducing metal content in edible plants.
must be done at a reasonable cost with minimal environmental impact. Therefore, treating contaminated
drinking water requires materials and approaches that are inexpensive, produced locally, and effortlessly. Hence,
locally available materials and their derivatives, such as biochar (BC) and activated carbon (AC) were investigated
thoroughly. Several researchers and their findings show that the application of locally accessible materials and their derivatives are capable of the adsorptive removal of organic and inorganic contaminants from drinking
water. The application of locally available materials such as lignocellulosic materials/waste and its thermochemically
derived products, including BC and AC were found effective in the treatment of contaminated
drinking water. Thus, this review aims to thoroughly examine the latest developments in the use of locally
accessible feedstocks for tailoring BC and AC, as well as their features and applications in the treatment of
drinking water. We attempted to explain facts related to the potential mechanisms of BC and AC, such as
complexation, co-precipitation, electrostatic interaction, and ion exchange to treat water, thereby achieving a
risk-free remediation approach to polluted water. Additionally, this research offers guidance on creating efficient
household treatment units based on the health risks associated with customized adsorbents and cost-benefit
analyses. Lastly, this review work discusses the current obstacles for using locally accessible materials and
their thermo-chemically.
production, high persistency in the environment, and unsustainable waste management practices. Therefore,
sustainable PW management and upcycling approaches are imperative to achieve the objectives of the United
Nations Sustainable Development Goals. Numerous recent studies have shown the application and feasibility of
various PW conversion techniques to produce materials with better economic value. Within this framework, the
current review provides an in-depth analysis of cutting-edge thermochemical technologies such as pyrolysis,
gasification, carbonization, and photocatalysis that can be used to value plastic and mixed PW in order to
produce energy and industrial chemicals. Additionally, a thorough examination of the environmental impacts of
contemporary PW upcycling techniques and their commercial feasibility through life cycle assessment (LCA) and
techno-economical assessment are provided in this review. Finally, this review emphasizes the opportunities and
challenges accompanying with existing PW upcycling techniques and deliver recommendations for future
research works.
storage, remediation of contaminated soil and water resources, mitigation of greenhouse gas emissions and
odorous compounds, and feed supplementation to improve animal health. A healthy soil preserves microbial
biodiversity that is effective in supressing plant pathogens and pests, recycling nutrients for plant growth,
promoting positive symbiotic associations with plant roots, improving soil structure to supply water and nutrients,
and ultimately enhancing soil productivity and plant growth. As a soil amendment, biochar assures soil
biological health through different processes. First, biochar supports habitats for microorganisms due to its
porous nature and by promoting the formation of stable soil micro-aggregates. Biochar also serves as a carbon
and nutrient source. Biochar alters soil physical and chemical properties, creating optimum soil conditions for
microbial diversity. Biochar can also immobilize soil pollutants and reduce their bioavailability that would
otherwise inhibit microbial growth. However, depending on the pyrolysis settings and feedstock resources,
biochar can be comprised of contaminants including polycyclic aromatic hydrocarbons and potentially toxic
elements that can inhibit microbial activity, thereby impacting soil health.
management. However, its recalcitrant chemical structure hinders microbial hydrolysis and reduces biomethane
production under AD. Biochar supplementation has been proven to promote the digestibility and biomethanation
of lignocellulosic substrates. Therefore, this study investigated the influence of different pyrolysis temperatures
(450 â—¦C, 550 â—¦C, and 650 â—¦C) on the physicochemical properties of biochar. Furthermore, the impact of ruminal
content biochar supplementation (1 %, 2 %, and 3 %) on the AD of rice straw with rumen fluid as inoculum has
been investigated. The ruminal content biochar (RUCB) supplemented reactors showed an increment in biomethane
yield and the highest cumulative biomethane yield 243.11 mL/g volatile solids (VS)) was recorded at 2
% RUCB supplementation, followed by 227.12 mL/g VS at 1 % RUCB supplementation and 162.86 mL/g VS at 3
% RUCB supplementation (P > 0.05). Compared to the control reactors (128.68 mL/g VS), RUCB supplemented
reactors exhibited 1.88-fold, 1.76-fold, and 1.26-fold increments in biomethane yield due to pH stabilization and
facilitation of microbial biofilm formation on the biochar. The correlation analysis showed that biomethane
production is positively correlated with VS reduction (R2 = 0.9852). This study proposed a potential strategy to
utilize ruminal content waste as a feedstock for biochar production and its application in AD for accelerating the
biomethanation of rice straw.
Plastic pollution and accumulation in water bodies have threatened the survival of marine life. Plastic
pollution can be prevented by using biopolymers that are eco-friendly and can be naturally produced by
certain living organisms. The biopolymers have environmental advantages over synthetic plastics, such
as biodegradability and biocompatibility. In comparison to plants and other microbial systems, bacteria
can accumulate a high amount of polyhydroxyalkanoates (PHAs). However, the major stumbling block in
the production of bacterial PHAs is its low cost-effectiveness due to costs associated with fermentaion
and down-stream processing. In consideration with the above properties, opportunities and challeges
associated with bacterial PHAs, this review focuses on structural diversity of PHAs, biosynthesis mechanism
in bacteria, biodegradation, life cycle analysis, and environmental impact of bioplastic production.
It further enumerates the advanced tools and techniques for bacterial PHA production, along with
various factors affecting the commercialization of bioplastics. Extraction methods, down-stream processing,
and biomedical applications of PHAs are also discussed. The opportunities and challenges in the
commercialization of bacterial PHAs along with future scenario and environmental sustainability are
presented for the purpose of fostering sustainable development.
conversion. Physicochemical and functional properties of BCs can be
enhanced by several methods of activation or functionalization. The activated
and functionalized BCs with a large surface area and abundant surface
functional groups can serve as effective catalysts or catalyst supports
for various chemical transformations as well as for adsorption/sorption/
enrichment of low-concentration pollutant streams. Among them, remediation
of environmental contaminants and production of a range of bioproducts in
biorefineries have attracted much attention in the context of achieving green
and sustainable development. Although the applications of BC as adsorbents
in removal of pollutants have been discussed extensively, there is a lot of
untapped potential with new applications of BCs as catalysts or catalyst supports
for advanced oxidation processes (AOPs) and sustainable biorefineries. In this
review, the production and activation/functionalization of BCs are scrutinized.
The mechanisms of activated and functionalized BC and BC-supported catalysts
in degradation of organic contaminants via AOPs assisted with hydrogen
peroxide (H2O2), peroxydisulfate (PDS), and peroxymonosulfate (PMS) are
reviewed. Emerging applications of BC as catalyst for production of biodiesel and
high-value chemicals, tar removal, bio-syngas reforming, and energy storage and
conversion devices are discussed in detail.
products. The variety of processes and pathways through which bio-valorization of algal biomass can be
performed are described in this review. Various lipid extraction techniques from algal biomass along with
transesterification reactions for biodiesel production are briefly discussed. Processes such as the pretreatment
and saccharification of algal biomass, fermentation, gasification, pyrolysis, hydrothermal liquefaction, and anaerobic
digestion for the production of biohydrogen, bio-oils, biomethane, biochar (BC), and various bio-based products
are reviewed in detail. The biorefinery model and its collaborative approach with various processes are
highlighted for the production of eco-friendly, sustainable, and cost-effective biofuels and value-added products.
The authors also discuss opportunities and challenges related to bio-valorization of algal biomass and use their
own perspective regarding the processes involved in production and the feasibility to make algal research a reality
for the production of biofuels and bio-based products in a sustainable manner.
the frequent use of pesticides can cause serious environmental problems due to their high accumulative
and persistent nature. Recently, microalgae technology has received considerable success in the efficient treatment
of pesticides pollution. In this review, the metabolic mechanisms responsible for the removal of pesticides
are summarized based on previous studies. Different methods used to enhance the ability of microalgae to remove
pesticides are critically evaluated. The recycling ofmicroalgae biomass afterwastewater treatment for biochar
preparation and biodiesel production using the biorefinery approach is also introduced. Furthermore, we
present potential future research directions to highlight the prospects of microalgae research in the removal of
pesticides along with the production of value-added products.
from macroalgae and microalgae and its utilization in anaerobic digestion (AD), aiming to achieve
zero waste and promote a circular economy. Biochar, a carbon-rich material derived through
pyrolysis or gasification, offers environmental and agricultural benefits due to its stability and
porosity. By incorporating biochar into AD systems, improved process efficiency, enhanced microbial
activity, and nutrient retention can be achieved. An integrated approach on its production
and application can minimize biomass disposal impacts, generate renewable energy, and improve
the soil and nutrient management. The use of macroalgae and microalgae for biochar production
aligns with the sustainability principles, as these resources have high growth rates and there is no
direct competition with the arable land. Thus, the focus of this article is to highlight the advances
in algal biochar production with emphasis to the factors influencing biochar properties, structure,
characterization, mechanism of biochar action, and the impact of biochar addition on AD. It also
evaluates the economic and environmental benefits, featuring the role of this approach in
achieving a zero-waste paradigm and supporting circular economy development.
and preserve their nutritional value as well as flavor. The currently used postharvest practices include different
physical, chemical, and biological processes. The most common physical methods encompass diverse methods
like treatments with hot water, thermal curing, light exposure, etc, whereas chemical methods include, hot
chemical drenches, application of fungicide, antimicrobial peptides, salicylic acid, nitric oxide, sulfur dioxide,
ozone, and other gaseous compounds, in addition to 1-methylcyclopropene (1-MCP) treatments. The biological
methods include the application of different biocontrol agents to effectively reduce the pathogenic
microorganisms.
Although all these treatments effectively reduce pathogenic microorganisms, particularly Penicillium species,
the information regarding their influence on the carposphere microflora of citrus fruits, including biocontrol
agents and beneficial microorganisms remains inadequately explored. Noteworthy, the carpophore of citrus
fruits harbors a variety of microbial communities having crucial role in preserving fruit’s natural environment
and defending host from postharvest pathogen attack. Therefore, the present review has discussed different
physical and chemical treatment practices employed during postharvest storage condition and their influence on
the native microflora of citrus carposphere.
environmental concerns, necessitating sustainable and eco-friendly alternatives for pest management. Therefore,
to find a complementary eco-friendly pesticide/nematicide, this study investigated the role of fly ash (FA) in
managing a notorious pest, Meloidogyne javanica and its impact on the growth and physiology of Abelmoschus
esculentus. Molecular characterization using SSU and LSU rDNA gene markers confirmed the identity of Indian
M. javanica as belonging to the same species. Biotic stress induced by nematode infection was significantly alleviated (P < 0.05) by FA application at a 20% w/v, regulating of ROS accumulation (44.1% reduction in
superoxide anions and 39.7% reduction in hydrogen peroxide content) in the host plant. Moreover, FA enhanced
antioxidant defence enzymes like superoxide dismutase (46.6%) and catalase (112%) to combat nematode
induced ROS. Furthermore, the application of FA at a 20% concentration significantly improved the biomass and
biochemical attributes of okra. Fly ash also upregulated the activity of the important osmo-protectant proline
(11.5 μmol/g FW) to mitigate nematode stress in host cells. Suppression of disease indices like gall index and
reproduction factor, combined with in-vitro experiments, revealed that FA exhibits strong nematode mortality
capacity and thus can be used as a sustainable and eco-friendly control agent against root-knot nematodes.
on soil microbial activity and diversity have not been sufficiently studied. Hence, a pot study was carried out to
investigate the effectiveness of ASB addition at 2, 4, and 6 % (w/w) on soil biochemical characteristics and the
bioavailability of Cd, Cu, Pb, and Zn to tomato (Solanum lycopersicum L.) plants, as compared to the control
(contaminated soil without ASB addition). The addition of ASB promoted plant growth (up to two-fold) and
restored the damage to the ultrastructure of chloroplast organelles. In addition, ASB mitigated the adverse effects
of HMs toxicity by decreasing oxidative damage, regulating the antioxidant system, improving soil physicochemical
properties, and enhancing enzymatic activities. At the phylum level, ASB addition enhanced the
relative abundance of Actinobacteriota, Acidobacteriota, and Firmicutes while decreasing the relative abundance of
Proteobacteria and Bacteroidota. Furthermore, ASB application increased the relative abundance of several fungal
taxa (Ascomycota and Mortierellomycota) while reducing the relative abundance of Basidiomycota in the soil. The
ASB-induced improvement in soil properties, microbial community, and diversity led to a significant decrease in
the DTPA-extractable HMs down to 41.0 %, 51.0 %, 52.0 %, and 35.0 % for Cd, Cu, Pb, and Zn, respectively, as
compared to the control. The highest doses of ASB (ASB6) significantly reduced the metals content by 26.0 % for
Cd, 78.0 % for Cu, 38.0 % for Pb, and 20.0 % for Zn in the roots, and 72.0 % for Cd, 67.0 % for Cu, 46.0 % for Pb,
and 35.0 % for Zn in the shoots, as compared to the control. The structural equation model predicts that soil pH
and organic matter are driving factors in reducing the availability and uptake of HMs. ASB could be used as a
sustainable trial for remediation of HMs polluted soils and reducing metal content in edible plants.
must be done at a reasonable cost with minimal environmental impact. Therefore, treating contaminated
drinking water requires materials and approaches that are inexpensive, produced locally, and effortlessly. Hence,
locally available materials and their derivatives, such as biochar (BC) and activated carbon (AC) were investigated
thoroughly. Several researchers and their findings show that the application of locally accessible materials and their derivatives are capable of the adsorptive removal of organic and inorganic contaminants from drinking
water. The application of locally available materials such as lignocellulosic materials/waste and its thermochemically
derived products, including BC and AC were found effective in the treatment of contaminated
drinking water. Thus, this review aims to thoroughly examine the latest developments in the use of locally
accessible feedstocks for tailoring BC and AC, as well as their features and applications in the treatment of
drinking water. We attempted to explain facts related to the potential mechanisms of BC and AC, such as
complexation, co-precipitation, electrostatic interaction, and ion exchange to treat water, thereby achieving a
risk-free remediation approach to polluted water. Additionally, this research offers guidance on creating efficient
household treatment units based on the health risks associated with customized adsorbents and cost-benefit
analyses. Lastly, this review work discusses the current obstacles for using locally accessible materials and
their thermo-chemically.
production, high persistency in the environment, and unsustainable waste management practices. Therefore,
sustainable PW management and upcycling approaches are imperative to achieve the objectives of the United
Nations Sustainable Development Goals. Numerous recent studies have shown the application and feasibility of
various PW conversion techniques to produce materials with better economic value. Within this framework, the
current review provides an in-depth analysis of cutting-edge thermochemical technologies such as pyrolysis,
gasification, carbonization, and photocatalysis that can be used to value plastic and mixed PW in order to
produce energy and industrial chemicals. Additionally, a thorough examination of the environmental impacts of
contemporary PW upcycling techniques and their commercial feasibility through life cycle assessment (LCA) and
techno-economical assessment are provided in this review. Finally, this review emphasizes the opportunities and
challenges accompanying with existing PW upcycling techniques and deliver recommendations for future
research works.
storage, remediation of contaminated soil and water resources, mitigation of greenhouse gas emissions and
odorous compounds, and feed supplementation to improve animal health. A healthy soil preserves microbial
biodiversity that is effective in supressing plant pathogens and pests, recycling nutrients for plant growth,
promoting positive symbiotic associations with plant roots, improving soil structure to supply water and nutrients,
and ultimately enhancing soil productivity and plant growth. As a soil amendment, biochar assures soil
biological health through different processes. First, biochar supports habitats for microorganisms due to its
porous nature and by promoting the formation of stable soil micro-aggregates. Biochar also serves as a carbon
and nutrient source. Biochar alters soil physical and chemical properties, creating optimum soil conditions for
microbial diversity. Biochar can also immobilize soil pollutants and reduce their bioavailability that would
otherwise inhibit microbial growth. However, depending on the pyrolysis settings and feedstock resources,
biochar can be comprised of contaminants including polycyclic aromatic hydrocarbons and potentially toxic
elements that can inhibit microbial activity, thereby impacting soil health.
management. However, its recalcitrant chemical structure hinders microbial hydrolysis and reduces biomethane
production under AD. Biochar supplementation has been proven to promote the digestibility and biomethanation
of lignocellulosic substrates. Therefore, this study investigated the influence of different pyrolysis temperatures
(450 â—¦C, 550 â—¦C, and 650 â—¦C) on the physicochemical properties of biochar. Furthermore, the impact of ruminal
content biochar supplementation (1 %, 2 %, and 3 %) on the AD of rice straw with rumen fluid as inoculum has
been investigated. The ruminal content biochar (RUCB) supplemented reactors showed an increment in biomethane
yield and the highest cumulative biomethane yield 243.11 mL/g volatile solids (VS)) was recorded at 2
% RUCB supplementation, followed by 227.12 mL/g VS at 1 % RUCB supplementation and 162.86 mL/g VS at 3
% RUCB supplementation (P > 0.05). Compared to the control reactors (128.68 mL/g VS), RUCB supplemented
reactors exhibited 1.88-fold, 1.76-fold, and 1.26-fold increments in biomethane yield due to pH stabilization and
facilitation of microbial biofilm formation on the biochar. The correlation analysis showed that biomethane
production is positively correlated with VS reduction (R2 = 0.9852). This study proposed a potential strategy to
utilize ruminal content waste as a feedstock for biochar production and its application in AD for accelerating the
biomethanation of rice straw.
Plastic pollution and accumulation in water bodies have threatened the survival of marine life. Plastic
pollution can be prevented by using biopolymers that are eco-friendly and can be naturally produced by
certain living organisms. The biopolymers have environmental advantages over synthetic plastics, such
as biodegradability and biocompatibility. In comparison to plants and other microbial systems, bacteria
can accumulate a high amount of polyhydroxyalkanoates (PHAs). However, the major stumbling block in
the production of bacterial PHAs is its low cost-effectiveness due to costs associated with fermentaion
and down-stream processing. In consideration with the above properties, opportunities and challeges
associated with bacterial PHAs, this review focuses on structural diversity of PHAs, biosynthesis mechanism
in bacteria, biodegradation, life cycle analysis, and environmental impact of bioplastic production.
It further enumerates the advanced tools and techniques for bacterial PHA production, along with
various factors affecting the commercialization of bioplastics. Extraction methods, down-stream processing,
and biomedical applications of PHAs are also discussed. The opportunities and challenges in the
commercialization of bacterial PHAs along with future scenario and environmental sustainability are
presented for the purpose of fostering sustainable development.
conversion. Physicochemical and functional properties of BCs can be
enhanced by several methods of activation or functionalization. The activated
and functionalized BCs with a large surface area and abundant surface
functional groups can serve as effective catalysts or catalyst supports
for various chemical transformations as well as for adsorption/sorption/
enrichment of low-concentration pollutant streams. Among them, remediation
of environmental contaminants and production of a range of bioproducts in
biorefineries have attracted much attention in the context of achieving green
and sustainable development. Although the applications of BC as adsorbents
in removal of pollutants have been discussed extensively, there is a lot of
untapped potential with new applications of BCs as catalysts or catalyst supports
for advanced oxidation processes (AOPs) and sustainable biorefineries. In this
review, the production and activation/functionalization of BCs are scrutinized.
The mechanisms of activated and functionalized BC and BC-supported catalysts
in degradation of organic contaminants via AOPs assisted with hydrogen
peroxide (H2O2), peroxydisulfate (PDS), and peroxymonosulfate (PMS) are
reviewed. Emerging applications of BC as catalyst for production of biodiesel and
high-value chemicals, tar removal, bio-syngas reforming, and energy storage and
conversion devices are discussed in detail.
products. The variety of processes and pathways through which bio-valorization of algal biomass can be
performed are described in this review. Various lipid extraction techniques from algal biomass along with
transesterification reactions for biodiesel production are briefly discussed. Processes such as the pretreatment
and saccharification of algal biomass, fermentation, gasification, pyrolysis, hydrothermal liquefaction, and anaerobic
digestion for the production of biohydrogen, bio-oils, biomethane, biochar (BC), and various bio-based products
are reviewed in detail. The biorefinery model and its collaborative approach with various processes are
highlighted for the production of eco-friendly, sustainable, and cost-effective biofuels and value-added products.
The authors also discuss opportunities and challenges related to bio-valorization of algal biomass and use their
own perspective regarding the processes involved in production and the feasibility to make algal research a reality
for the production of biofuels and bio-based products in a sustainable manner.
the frequent use of pesticides can cause serious environmental problems due to their high accumulative
and persistent nature. Recently, microalgae technology has received considerable success in the efficient treatment
of pesticides pollution. In this review, the metabolic mechanisms responsible for the removal of pesticides
are summarized based on previous studies. Different methods used to enhance the ability of microalgae to remove
pesticides are critically evaluated. The recycling ofmicroalgae biomass afterwastewater treatment for biochar
preparation and biodiesel production using the biorefinery approach is also introduced. Furthermore, we
present potential future research directions to highlight the prospects of microalgae research in the removal of
pesticides along with the production of value-added products.
on the production market, to satisfy the demands and desire of society. The
recently developed production and consumption models largely rely on fossil-based
resources, which are affecting the environment and natural resources adversely. The
cost-effective production of biological materials is an emerging sector with remarkable
future prospects and provides many business opportunities. With time the
research endeavors are gradually shifting toward bacterial lipids-derived biofuel
production, which is more suitable and compatible for an industrial application. The
major challenge in the overall process of the production of lipids-derived fuels from
microbes is the involved carbon source as it contributes to more than half of the
production cost. Therefore the production of lipids and biodiesel from bacteria
using different waste materials as carbon source involving the application of
advanced biotechnological tools, and modified transesterification reactions will
make the biodiesel production cost effective.