A major challenge to commercial production of cellulosic ethanol pertains to the costeffective br... more A major challenge to commercial production of cellulosic ethanol pertains to the costeffective breakdown of the complex and recalcitrant structure of lignocellulose into its components by pretreatment methods—physical, chemical, physico-chemical, biological and various combinations thereof. The type and conditions of a pretreatment impacts both upstream processes such as size reduction as well as downstream processes such as enzymatic hydrolysis and enzyme loadings, and as such the choice of a pretreatment method for a specific biomass (or mix of materials) is influenced by several factors such as carbohydrate preservation and digestibility, sugar and ethanol yields, energy consumption, equipment and solvent costs, lignin removal and quality, formation of sugar/lignin degradation products, waste production, and water usage, among others. This chapter reviews both well-known and emerging physico-chemical methods of biomass fractionation with regards to process description and applica...
Processing of fruits in Ghana leads to the generation of tonnes of waste such as peels, seeds, co... 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...
Despite the abundance of diverse biomass resources in Africa, they have received little research ... 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...
Green seaweeds (Chlorophyta) are often considered a nuisance, but may in fact constitute a potent... 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.
The saccharification of biomass with hydrolases from fungi is considered as an efficient and sust... 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 sust... 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, ... 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.
Plastic waste such as polyethylene, with a calorifi c value of 46.2 kJ/g, has the potential to gr... 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 y... 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 ...
This study was conducted to improve the voltage production, desalination, and COD removal efficie... 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....
Fluctuating oil prices and its increasing environmental concerns have revived widespread interest... 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...
A major challenge to commercial production of cellulosic ethanol pertains to the costeffective br... more A major challenge to commercial production of cellulosic ethanol pertains to the costeffective breakdown of the complex and recalcitrant structure of lignocellulose into its components by pretreatment methods—physical, chemical, physico-chemical, biological and various combinations thereof. The type and conditions of a pretreatment impacts both upstream processes such as size reduction as well as downstream processes such as enzymatic hydrolysis and enzyme loadings, and as such the choice of a pretreatment method for a specific biomass (or mix of materials) is influenced by several factors such as carbohydrate preservation and digestibility, sugar and ethanol yields, energy consumption, equipment and solvent costs, lignin removal and quality, formation of sugar/lignin degradation products, waste production, and water usage, among others. This chapter reviews both well-known and emerging physico-chemical methods of biomass fractionation with regards to process description and applica...
Processing of fruits in Ghana leads to the generation of tonnes of waste such as peels, seeds, co... 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...
Despite the abundance of diverse biomass resources in Africa, they have received little research ... 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...
Green seaweeds (Chlorophyta) are often considered a nuisance, but may in fact constitute a potent... 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.
The saccharification of biomass with hydrolases from fungi is considered as an efficient and sust... 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 sust... 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, ... 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.
Plastic waste such as polyethylene, with a calorifi c value of 46.2 kJ/g, has the potential to gr... 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 y... 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 ...
This study was conducted to improve the voltage production, desalination, and COD removal efficie... 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....
Fluctuating oil prices and its increasing environmental concerns have revived widespread interest... 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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