- Ghana
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Processing of fruits in Ghana leads to the generation of tonnes of waste such as peels, seeds, cores and crowns. Handling this waste tends to be a major challenge. The usual practice is to discard these wastes in drainages, water bodies... more
Processing of fruits in Ghana leads to the generation of tonnes of waste such as peels, seeds, cores and crowns. Handling this waste tends to be a major challenge. The usual practice is to discard these wastes in drainages, water bodies and in landfills. However, if these wastes are used as feedstock to produce enzymes, bioethanol, and specialty chemicals instead of being dumped in landfills or put in the ocean, this unwanted environmental pollution can be avoided. Utilizing these wastes as a resource for energy production such as bioethanol, which is produced from the fermentation of reducing sugars is a means of addressing the sanitation issue while valorizing the waste. The main aim of this work was to use Response Surface Methodology, to estimate conditions for the optimal production of reducing sugars from fruit wastes via hydrolysis using enzymes. The substrate used compromised of pineapple peels, pawpaw peels, mango peels and a blend of these three fruit peels. Fruit waste sa...
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Raw images used for creation of Figure 4 and 5.
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Despite the abundance of diverse biomass resources in Africa, they have received little research and development focus. This study presents compositional analysis, sugar, and ethanol yields of hydrothermal pretreated (195 °C, 10 min)... more
Despite the abundance of diverse biomass resources in Africa, they have received little research and development focus. This study presents compositional analysis, sugar, and ethanol yields of hydrothermal pretreated (195 °C, 10 min) biomass from West Africa, including bamboo wood, rubber wood, elephant grass, Siam weed, and coconut husk, benchmarked against those of wheat straw. The elephant grass exhibited the highest glucose and ethanol yields at 57.8% and 65.1% of the theoretical maximums, respectively. The results show that the glucose yield of pretreated elephant grass was 3.5 times that of the untreated material, while the ethanol yield was nearly 2 times higher. Moreover, the sugar released by the elephant grass (30.8 g/100 g TS) was only slightly lower than by the wheat straw (33.1 g/100 g TS), while the ethanol yield (16.1 g/100 g TS) was higher than that of the straw (15.26 g/100 g TS). All other local biomass types studied exhibited sugar and ethanol yields below 33% and...
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Green seaweeds (Chlorophyta) are often considered a nuisance, but may in fact constitute a potential climate-friendly renewable resource in the new bioeconomy. Utilization of green seaweed polysaccharides could in particular enable a new... more
Green seaweeds (Chlorophyta) are often considered a nuisance, but may in fact constitute a potential climate-friendly renewable resource in the new bioeconomy. Utilization of green seaweed polysaccharides could in particular enable a new type of green growth in coastal regions in developing countries e.g. in West Africa. The carbohydrate constituents, including cellulose, are lignin-free, but only limited knowledge is available on the cellulose ultrastructure and cellulose crystallinity in commonly occurring green seaweeds. Abundantly available green seaweeds along the coast in West Africa include Chaetomorpha linum, Caulerpa taxifolia, Ulva fasciata and Ulva flexuosa. Here, using X-ray diffraction (XRD), on cellulose gently purified from the green seaweeds, we determined that mainly cellulose Iα was present in both C. linum and U. flexuosa. We also found that the crystallite diameter was particularly large, 16 nm, in both the Ghanaian and the Danish C. linum samples, especially compared to the crystallite diameter of 2.5–5 nm in most terrestrial vascular plants (Tracheophytes), which mainly contain cellulose Iβ. For U. flexuosa, increasing crystallinity of the cellulose was achieved during purification. Cellulose purification was not achievable for C. taxifolia, indicating that in this species the glucose is mainly a constituent of other carbohydrates, presumably notably of starch. Transmission electron microscopy (TEM) confirmed the large size of the crystallites of C. linum showing the cellulose forming a multi-lamellar structure with alternating perpendicular and parallel layers along the fibre axis. The cell wall nano-structure appeared amorphous in C. taxifolia and as a network in U. fasciata and U. flexuosa. As glucose was most abundant in C. linum and its cellulose was crystalline, this green seaweed species appears particularly promising as a source for manufacturing of novel cellulose-based materials, e.g. specialized paper or cellulose-based composite materials.
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The saccharification of biomass with hydrolases from fungi is considered as an efficient and sustainable approach to obtain fermentable sugars. The expression of these hydrolytic enzymes by fungi is mainly by a substrate-induced... more
The saccharification of biomass with hydrolases from fungi is considered as an efficient and sustainable approach to obtain fermentable sugars. The expression of these hydrolytic enzymes by fungi is mainly by a substrate-induced mechanism, which depends on prevailing environmental conditions. <i>Trametes polyzona, </i>a white rot fungus, is regarded as one of the most efficient producers of hydrolases for the hydrolysis of biomass. This study sought to examine and optimize cultivation conditions for the efficient production of hydrolases by <i>Trametes polyzona </i>(<i>T. polyzona</i>)<i>. </i>Hydrolase production by <i>T. polyzona</i> was examined using parametric optimization. Crude enzyme extracts obtained under varying cultivation conditions were profiled for endoglucanase, betaglucosidase, exoglucanase, xylanase and amylase activities to determine the optimal conditions for hydrolase production. Maximum hydrolase produ...
The saccharification of biomass with hydrolases from fungi is considered as an efficient and sustainable approach to obtain fermentable sugars. The expression of these hydrolytic enzymes by fungi is mainly by a substrate-induced... more
The saccharification of biomass with hydrolases from fungi is considered as an efficient and sustainable approach to obtain fermentable sugars. The expression of these hydrolytic enzymes by fungi is mainly by a substrate-induced mechanism, which depends on prevailing environmental conditions. <i>Trametes polyzona, </i>a white rot fungus, is regarded as one of the most efficient producers of hydrolases for the hydrolysis of biomass. This study sought to examine and optimize cultivation conditions for the efficient production of hydrolases by <i>Trametes polyzona </i>(<i>T. polyzona</i>)<i>. </i>Hydrolase production by <i>T. polyzona</i> was examined using parametric optimization. Crude enzyme extracts obtained under varying cultivation conditions were profiled for endoglucanase, betaglucosidase, exoglucanase, xylanase and amylase activities to determine the optimal conditions for hydrolase production. Maximum hydrolase produ...
Bioethanol from lignocellulosic biomass poses as a sustainable alternative to gasoline. However, the high cost of pretreatment and hydrolysis of lignocellulosic biomass tends to limit their utilization as feedstock for ethanol... more
Bioethanol from lignocellulosic biomass poses as a sustainable alternative to gasoline. However, the high cost of pretreatment and hydrolysis of lignocellulosic biomass tends to limit their utilization as feedstock for ethanol biorefinery. This study therefore sought to convert cassava (CRI-Abrabopa) peels into ethanol using the on-site tailored enzyme production approach. Fungi were isolated from CRI-Abrabopa peels by the spread and direct plate techniques. Isolates obtained were subjected to morphological identification and molecular characterization by sequencing ITS spacer genes (rRNA). On-site tailored enzymes were produced from the most potent lignocellulolytic fungus. On-site and off-site (CTEC 2) enzymes were used to hydrolyse peels before fermenting to ethanol using Saccharomyces cerevisiae. CRI-Abrabopa peels were found to be a highly efficient feedstock for bioethanol production due to their rich-sugar content (78.3% dry biomass). Molecular characterization of the most potent lignocellulolytic isolate revealed it as Trametes polyzona BKW-001. Its profile revealed the presence of cellulases, xylanases, and amylases, with the amylase activity being the most pronounced at 56.2 U/mL. The on-site tailored enzyme production approach used in this study proved to be an efficient alternative to the commercial off-site enzyme preparation with a comparative sugar recovery efficiency of up to 90%. An ethanol yield of 28.8 g/100 g reducing sugars (on-site enzyme derived) was obtained from the cassava peels. Findings from this study have demonstrated the suitability and possible adoption of on-site tailored enzyme application in conventional ethanol biorefinery.
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Plastic waste such as polyethylene, with a calorifi c value of 46.2 kJ/g, has the potential to greatly supplement the energy requirements of clay pozzolana production. This was tested when 0.08 g of plastic was embedded in 8 g of clay... more
Plastic waste such as polyethylene, with a calorifi c value of 46.2 kJ/g, has the potential to greatly supplement the energy requirements of clay pozzolana production. This was tested when 0.08 g of plastic was embedded in 8 g of clay before its calcination in a furnace. It was observed that the energy consumption of the furnace was reduced signi ficantly with increasing plastic to clay ratio. The compressive s trength of the pozzolana-OPC (Pozzolana-Ordinary Portland Cement) composite blocks was also comparatively higher. The use of plastic waste in the production of pozzolan a can thus reduce the cost of building as well as reduce carbon dioxide emissions.
This study investigated the effect of three different types of microbial activity on bioethanol yield from cassava peelings. The cassava peelings were pretreated by milling to 2mm particle size, autoclaved and hydrolyzed using Pleurotus... more
This study investigated the effect of three different types of microbial activity on bioethanol yield from cassava peelings. The cassava peelings were pretreated by milling to 2mm particle size, autoclaved and hydrolyzed using Pleurotus ostreatus k910 (white-rot fungi), Aspergillus niger Menae1 (black molds) and a combination of the two fungi. The hydrolysates obtained were subsequently fermented to ethanol using the Saccharomyces cerevisiae (baker’s yeast). The analysis of lignocellulose fractions, fermentable sugars and bioethanol produced were performed using a van Soest, refractometry and gravimetric methods respectively. The effect of the various fungi used for biological pretreatment/hydrolysis on lignocellulose fractions and fermentable sugars released of each substrate were studied. P. otreatus k910 hydrolysis of the cassava peelings yielded an optimum fermentable sugar concentration of 34.11 g/L compared to 28.64 g/l for the A. niger MENAE1. However, the combination of the ...
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This study was conducted to improve the voltage production, desalination, and COD removal efficiencies of a five-chamber Microbial Desalination Cell (MDC). To do this, rhamnolipid was added to anolytes only and catholytes stirred to... more
This study was conducted to improve the voltage production, desalination, and COD removal efficiencies of a five-chamber Microbial Desalination Cell (MDC). To do this, rhamnolipid was added to anolytes only and catholytes stirred to determine the effects of these factors on the MDC activity. This was followed by a factorial study to investigate the effects of the interactions of rhamnolipid and stirring on the voltage production, desalination, and COD removal efficiencies of the MDC. Increasing the concentration of rhamnolipid to 240 mg/L improved the peak voltage produced from 164.50 ± 0.11 to 623.70 ± 1.32 mV. Also, the desalination efficiency increased from 20.16 ± 1.97 % when no rhamnolipid was added to 24.89 ± 0.50 % at a rhamnolipid concentration of 240 mg/L, and COD removal efficiency increased from 48.74 ± 8.06 % to 64.17 ± 5.00 % at a rhamnolipid concentration of 400 mg/L. In the stirring experiments, increasing the number of stirring events increased peak voltage from 164....
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Fluctuating oil prices and its increasing environmental concerns have revived widespread interest in production of biofuel from renewable (lignocellulose) materials. Rice husk and cassava peelings (agro-wastes with little or negligible... more
Fluctuating oil prices and its increasing environmental concerns have revived widespread interest in production of biofuel from renewable (lignocellulose) materials. Rice husk and cassava peelings (agro-wastes with little or negligible values to industries in Ghana) were evaluated as a substitute cost effective feed stock for bioethanol production. This project investigated second-generation bioethanol production by pretreating and hydrolysing agro-waste using Pleurotus ostreatus, Aspergillus niger and a combination of the two fungi. The various hydrolysates obtained were subsequently fermented to ethanol using Saccharomyces cerevisiae. The analysis of lignocellulose fractions was conducted using van Soest refractometer whilst fermentable sugars and bioethanol produced were analysed using gravimetric method. The combination of the fungi gave a better yield of fermentable sugars compared to the yield obtained from hydrolysis by either P. ostreatus or A. niger. Of the two fungi, P. os...
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In developing countries, local enzyme production can help decrease the dependency of imported enzymes for bioconversion of e.g. cellulosic feedstocks, but the use of conventional nitrogen sources contributes significantly to such enzyme... more
In developing countries, local enzyme production can help decrease the dependency of imported enzymes for bioconversion of e.g. cellulosic feedstocks, but the use of conventional nitrogen sources contributes significantly to such enzyme production cost. Use of local resources is therefore important to consider. Green seaweeds are marine macroalgae that are rich in nitrogen, but not exploited for their nitrogen content. Cellulase production was accomplished by using cocoa pod husk (CPH) and green seaweed (GS) (Ulvafasciata sp.) as growth substrates for Polyporusciliatus CBS 366.74 in submerged cultivation. The nitrogen concentration of GS was comparable to that of CPH with 0.6% w/v peptone at 4% w/v substrate concentration. A decline of cellulase activity in peptone supplemented GS growth media indicated nitrogen sufficiency of GS to serve as a potential nitrogen source for the fungal growth and cellulase production. Comparison of enzyme production on CPH growth media supplemented with either GS or peptone based on equivalent carbon to nitrogen ratios was done for two Polyporus strains namely; P. ciliatus CBS 366.74 and P. brumalis CBS 470.77. Peptone could be substituted by up to 0.6% w/v with GS at inclusion levels of 50–100% of substrate concentration to attain satisfactory cellulase productivity. However, the cellulase productivity response varied among the two Polyporus species. This study demonstrated that green seaweeds may be used as alternative nitrogen sources for fungal cellulase production.
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The rapid depletion and environmental concerns associated with the use of fossil fuels has led to extensive development of biofuels such as bioethanol from seaweeds. The long-term prospect of seaweed bioethanol production however, depends... more
The rapid depletion and environmental concerns associated with the use of fossil fuels has led to extensive development of biofuels such as bioethanol from seaweeds. The long-term prospect of seaweed bioethanol production however, depends on the selection of processes in the hydrolysis and fermentation stages due to their limiting effect on ethanol yield. This review explored the factors influencing the hydrolysis and fermentation stages of seaweed bioethanol production with emphasis on process efficiency and sustainable application. Seaweed carbohydrate contents which are most critical for ethanol production substrate selection were 52 ± 6%, 55 ± 12% and 57 ± 13% for green, brown and red seaweeds, respectively. Inhibitor formation and polysaccharide selectivity were found to be the major bottlenecks influencing the efficiency of dilute acid and enzymatic hydrolysis, respectively. Current enzyme preparations used, were developed for starch-based and lignocellulosic biomass but not s...
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White-rot basidiomycetous (WRB) fungi are a group of wood-decaying fungi that are known to be endowed with the ability to secrete enzymes that can catalyze decomposition of a range of plant cell wall polysaccharides, including cellulose... more
White-rot basidiomycetous (WRB) fungi are a group of wood-decaying fungi that are known to be endowed with the ability to secrete enzymes that can catalyze decomposition of a range of plant cell wall polysaccharides, including cellulose and lignin. Expression of these enzymes is induced by the substrate and the enzyme yields obtained depend on the growth of the fungi and thus the mode of cultivation. In order to exploit WRB fungi for local enzyme production for converting lignocellulosic materials in biorefinery processes, the fungi can principally be cultivated in either solid-state (SSC) or submerged cultivation (SmC) systems. In this review, we quantitatively assess the data available in the literature on cellulase production yields by WRB fungi cultivated by SSC or SmC. The review also assesses cellulolytic enzyme production rates and enzyme recovery when WRB fungi are cultivated on different biomass residues in SSC or SmC systems. Although some variation in cellulase production...
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ABSTRACT
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Pretreatment of lignocellulose has received considerable research globally due to its influence on the technical, economic and environmental sustainability of cellulosic ethanol production. Some of the most promising pretreatment methods... more
Pretreatment of lignocellulose has received considerable research globally due to its influence on the technical, economic and environmental sustainability of cellulosic ethanol production. Some of the most promising pretreatment methods require the application of chemicals such as acids, alkali, salts, oxidants, and solvents. Thus, advances in research have enabled the development and integration of chemical-based pretreatment into proprietary ethanol production technologies in several pilot and demonstration plants globally, with potential to scale-up to commercial levels. This paper reviews known and emerging chemical pretreatment methods, highlighting recent findings and process innovations developed to offset inherent challenges via a range of interventions, notably, the combination of chemical pretreatment with other methods to improve carbohydrate preservation, reduce formation of degradation products, achieve high sugar yields at mild reaction conditions, reduce solvent load...
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This study was designed to select potential areas for the cultivation of seaweeds on the Ghanaian coastline. The challenge of selecting suitable sites for the cultivation of seaweed along the coast was investigated, using spatial... more
This study was designed to select potential areas for the cultivation of seaweeds on the Ghanaian coastline. The challenge of selecting suitable sites for the cultivation of seaweed along the coast was investigated, using spatial multi-criteria approach in GIS. Environmental and physical parameters based on spatial multi-criteria decision for the best sites suitable for seaweed cultivation were used. The parameters used included Sea-depth (1-10)m, (11-20)m, (21-30)m and (31-40)m, sea-surface temperature (24-26) degree Celsius, proximity to settlements (0-8) kilometers and sheltered coves (areas sheltered from strong wind and waves) as variables for the various models. The study identified twelve suitable sites along the coast of Ghana for seaweed cultivation. Five of the selected sites were ground-truthed for model validation. All five validation sites have agreed to the GIS models indicating that GIS is the most appropriate tool to use for selecting most suitable environment for se...
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Background: Faecal sludge (FS) represents a huge resource, which when tapped and made use properly can be of great benefit to many. However, the key to tapping this resource lies in proper characterisation, in order to make known the... more
Background: Faecal sludge (FS) represents a huge resource, which when tapped and made use properly can be of great benefit to many. However, the key to tapping this resource lies in proper characterisation, in order to make known the constituents and thereby determine the end-use. Methods: Three sources of FS from 43 communities in the Kumasi metropolis of Ghana were characterised in terms of their total solids content, chemical oxygen demand (COD), pH, nitrogen, phosphorous and lipid contents. FS from pit latrines, public septage and private septage were analysed. Results: On average, lipid content was found to be in the range of 8.82 – 9.66% of dry FS depending on the source of FS. Total solids were between 0.79 and 4.68%, while the COD was between 9495 and 45611mg/L. Phosphorus content was in the range of 137 – 520mg/L, while nitrogen was 649 – 4479mg/L. Most FS samples were generally alkaline in nature. Conclusions: These results are amongst the first long-term characterization ...