A major challenge in the biodiesel industry is the comparatively high cost of raw materials for p... more A major challenge in the biodiesel industry is the comparatively high cost of raw materials for production. A cost build-up analysis of biodiesel production from J. curcas oil shows that catalyst alone contributes about 50.9% of the total production cost. This paper aims at highlighting the effects of two different commonly used catalysts on the yield of biodiesel. Samples of biodiesel were produced by three different methods namely single stage transesterification (SST), double stage transesterification (DST) and foolproof (FP) processes in which sodium hydroxide (NaOH) and potassium hydroxide (KOH) were used. The effects of each catalyst on the production yield were analyzed and compared. NaOH gave production yields of 79%, 81% and 84% for the SST, DST and FP processes respectively. KOH produced comparatively lower yields of 68%, 71% and 75% for SST, DST and fool proof processes respectively. Although the use of KOH slightly raises the cost of biodiesel production as compared to NaOH, the local production of KOH from cocoa husks could minimize the production cost.
International Journal of Energy and Water Resources, 2019
Microbial desalination cell, a versatile technology for simultaneous wastewater treatment, desali... more Microbial desalination cell, a versatile technology for simultaneous wastewater treatment, desalination and power generation is hoped to solve the critical needs (water and energy) of the world. However, to achieve these, sustainable cathode is required. Thus, this research investigated the potential of Ceratophyllum demersum for the construction of an efficient and environmentally friendly biocathode. With the plant biocathode, a plant microbial desalination cell was developed which was able to cause a 10.22% desalination of a 35 g/l salt solution in a batch cycle. Though the maximum voltage produced was small (154 ± 0.33 mV), the cell was, however, able to achieve a 41.79% COD reduction from an initial of 645 ± 2.3 mg/l using 1.05% nitrate and 9.97% phosphorus in wastewater. Unsuitable growth conditions for the survival of C. demersum and high internal resistance of the PMDC were identified as the main causes of the low peak voltage and percentage desalination produced by this cell. Future research on plant microbial desalination cells should consider solving the stated challenges.
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...
Biogas Technology in Ghana is relatively underdeveloped and has been limited to donor-funded proj... more Biogas Technology in Ghana is relatively underdeveloped and has been limited to donor-funded projects in communal areas and health institutions. In most cases the projects have been abandoned for lack of sustained funding, poor maintenance and management. Where there is any technical utilization of the technology, these have been limited to the production of Biogas for heating water and for cooking purposes with little or poor maintenance of the equipment used.. A survey carried out by the authors indicated that in almost all cases there is an under-utilisation of the gas produced. The Ministry of Energy, whilst recognising the growing importance of renewable energy in meeting the policy objectives of securing future energy for strategic applications in addition to minimising the environmental impacts of energy supply, particularly in a country that has no known appreciable reserves of oil, it has not come out with a clear policy statement for the research, development and promotion of biogas technology. The present study focuses on the development of biogas technology for industrial application in the Kumasi Abattoir, through the use of the animal waste produced for the production of Biogas, namely for heat and electricity generation with the resultant effect of creating an economically viable and thereby sustained venture for the private sector..
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...
The biodegradable fraction of municipal solid wastes generated from households in Ghana has favou... more The biodegradable fraction of municipal solid wastes generated from households in Ghana has favourable characteristics worth considering for bioenergy production. The suitability of this biodegradable portion for biogas and bioethanol production was assessed in this study. The assessment was performed on both untreated and hydrothermally treated unsorted and sorted fractions of the waste using standard methods for biomass conversion to bioenergy. Compositional analysis of the waste indicated that unsorted biodegradable municipal solid wastes (BMSW) consisted of 38.7 % dry matter (DM) glucan, 8.3 % DM hemicellulose, 10.1 % DM lignin and 7.6 % DM ash. The sorted fractions with the highest glucan but least lignin and hemicellulose were the pool of cassava, yam and plantain peeling wastes (CYPPW) with 84 % DM glucan much of which was starch, 5.6 % DM lignin and 0.5 % DM hemicellulose. The highest ethanol yield of 0.29 l/kg DM was measured from this same CYPPW while fruit wastes (FW) had the highest biomethane potential of 408 ml CH 4 /g VS. The BMSW had ethanol yield of 0.17 l/ kg DM and biogas 369 ml CH 4 /g VS. The hydrothermally pretreated wastes had marginal increases in glucose and ethanol yield except the treated yard waste which significantly increased by 54 % in glucose over the untreated waste. The most promising waste fractions were FW, CYPPW and mixed paper wastes. Careful selection of these fractions in feedstock for biofuel production would reduce generation of the waste, improve the quality and effectively lead to higher yield of biofuel over the unsorted form.
PEER-REVIEWED ARTICLE Ethanol Production from Hydrothermally-Treated Biomass from West Africa
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...
A major challenge to commercial production of cellulosic ethanol pertains to the cost-effective b... more A major challenge to commercial production of cellulosic ethanol pertains to the cost-effective breakdown of the complex and recalcitrant structure of lignocellulose into its components via pretreatment, the cost of enzymes for hydrolysis and fermentation, and the conversion rate of C5 sugars to ethanol, among others. While the industrialized and some emerging countries are gradually breaking grounds in cellulosic ethanol, most African countries have made little effort in research and development even though the continent is rich in lignocellulosic biomass. The paper estimates residues from widely available crops and municipal waste and determines their respective theoretical ethanol potential (around 22 billion litres annually). It further reviews stages involved in the production of cellulosic ethanol, focussing on processing methods that can be adapted to current situation in most African countries. The paper suggests that research and development should highlight favourable pretreatment methods such as extrusion, steaming/boiling, and chemical methods employing lime, KOH and crude glycerol (from biodiesel production), as well as the development of crude enzyme complexes from local materials. Though the falling price of enzymes is improving economic production of ethanol, advancements in heterogeneous catalytic hydrolysis will considerably favour economic production of ethanol in Africa due to the potential of recycling and reusing solid acid catalysts.
Cell wall configuration and ultrastructure of cellulose crystals in green seaweeds
Cellulose, 2021
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.
Optimization of Hydrolase Production (Dataset).pdf
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...
Optimization of Hydrolases Production (Dataset).pdf
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...
Conversion of cassava peels into bioethanol using the OSTEP approach
Biomass Conversion and Biorefinery, 2022
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.
The Production of Pozzolana Using High Calorific Waste
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.
Effect of Different Sets of Pleurotus ostreatus and Aspergillus niger Hydrolysis of Cassava Peelings on Bioethanol Yield
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 in the biodiesel industry is the comparatively high cost of raw materials for p... more A major challenge in the biodiesel industry is the comparatively high cost of raw materials for production. A cost build-up analysis of biodiesel production from J. curcas oil shows that catalyst alone contributes about 50.9% of the total production cost. This paper aims at highlighting the effects of two different commonly used catalysts on the yield of biodiesel. Samples of biodiesel were produced by three different methods namely single stage transesterification (SST), double stage transesterification (DST) and foolproof (FP) processes in which sodium hydroxide (NaOH) and potassium hydroxide (KOH) were used. The effects of each catalyst on the production yield were analyzed and compared. NaOH gave production yields of 79%, 81% and 84% for the SST, DST and FP processes respectively. KOH produced comparatively lower yields of 68%, 71% and 75% for SST, DST and fool proof processes respectively. Although the use of KOH slightly raises the cost of biodiesel production as compared to NaOH, the local production of KOH from cocoa husks could minimize the production cost.
International Journal of Energy and Water Resources, 2019
Microbial desalination cell, a versatile technology for simultaneous wastewater treatment, desali... more Microbial desalination cell, a versatile technology for simultaneous wastewater treatment, desalination and power generation is hoped to solve the critical needs (water and energy) of the world. However, to achieve these, sustainable cathode is required. Thus, this research investigated the potential of Ceratophyllum demersum for the construction of an efficient and environmentally friendly biocathode. With the plant biocathode, a plant microbial desalination cell was developed which was able to cause a 10.22% desalination of a 35 g/l salt solution in a batch cycle. Though the maximum voltage produced was small (154 ± 0.33 mV), the cell was, however, able to achieve a 41.79% COD reduction from an initial of 645 ± 2.3 mg/l using 1.05% nitrate and 9.97% phosphorus in wastewater. Unsuitable growth conditions for the survival of C. demersum and high internal resistance of the PMDC were identified as the main causes of the low peak voltage and percentage desalination produced by this cell. Future research on plant microbial desalination cells should consider solving the stated challenges.
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...
Biogas Technology in Ghana is relatively underdeveloped and has been limited to donor-funded proj... more Biogas Technology in Ghana is relatively underdeveloped and has been limited to donor-funded projects in communal areas and health institutions. In most cases the projects have been abandoned for lack of sustained funding, poor maintenance and management. Where there is any technical utilization of the technology, these have been limited to the production of Biogas for heating water and for cooking purposes with little or poor maintenance of the equipment used.. A survey carried out by the authors indicated that in almost all cases there is an under-utilisation of the gas produced. The Ministry of Energy, whilst recognising the growing importance of renewable energy in meeting the policy objectives of securing future energy for strategic applications in addition to minimising the environmental impacts of energy supply, particularly in a country that has no known appreciable reserves of oil, it has not come out with a clear policy statement for the research, development and promotion of biogas technology. The present study focuses on the development of biogas technology for industrial application in the Kumasi Abattoir, through the use of the animal waste produced for the production of Biogas, namely for heat and electricity generation with the resultant effect of creating an economically viable and thereby sustained venture for the private sector..
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...
The biodegradable fraction of municipal solid wastes generated from households in Ghana has favou... more The biodegradable fraction of municipal solid wastes generated from households in Ghana has favourable characteristics worth considering for bioenergy production. The suitability of this biodegradable portion for biogas and bioethanol production was assessed in this study. The assessment was performed on both untreated and hydrothermally treated unsorted and sorted fractions of the waste using standard methods for biomass conversion to bioenergy. Compositional analysis of the waste indicated that unsorted biodegradable municipal solid wastes (BMSW) consisted of 38.7 % dry matter (DM) glucan, 8.3 % DM hemicellulose, 10.1 % DM lignin and 7.6 % DM ash. The sorted fractions with the highest glucan but least lignin and hemicellulose were the pool of cassava, yam and plantain peeling wastes (CYPPW) with 84 % DM glucan much of which was starch, 5.6 % DM lignin and 0.5 % DM hemicellulose. The highest ethanol yield of 0.29 l/kg DM was measured from this same CYPPW while fruit wastes (FW) had the highest biomethane potential of 408 ml CH 4 /g VS. The BMSW had ethanol yield of 0.17 l/ kg DM and biogas 369 ml CH 4 /g VS. The hydrothermally pretreated wastes had marginal increases in glucose and ethanol yield except the treated yard waste which significantly increased by 54 % in glucose over the untreated waste. The most promising waste fractions were FW, CYPPW and mixed paper wastes. Careful selection of these fractions in feedstock for biofuel production would reduce generation of the waste, improve the quality and effectively lead to higher yield of biofuel over the unsorted form.
PEER-REVIEWED ARTICLE Ethanol Production from Hydrothermally-Treated Biomass from West Africa
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...
A major challenge to commercial production of cellulosic ethanol pertains to the cost-effective b... more A major challenge to commercial production of cellulosic ethanol pertains to the cost-effective breakdown of the complex and recalcitrant structure of lignocellulose into its components via pretreatment, the cost of enzymes for hydrolysis and fermentation, and the conversion rate of C5 sugars to ethanol, among others. While the industrialized and some emerging countries are gradually breaking grounds in cellulosic ethanol, most African countries have made little effort in research and development even though the continent is rich in lignocellulosic biomass. The paper estimates residues from widely available crops and municipal waste and determines their respective theoretical ethanol potential (around 22 billion litres annually). It further reviews stages involved in the production of cellulosic ethanol, focussing on processing methods that can be adapted to current situation in most African countries. The paper suggests that research and development should highlight favourable pretreatment methods such as extrusion, steaming/boiling, and chemical methods employing lime, KOH and crude glycerol (from biodiesel production), as well as the development of crude enzyme complexes from local materials. Though the falling price of enzymes is improving economic production of ethanol, advancements in heterogeneous catalytic hydrolysis will considerably favour economic production of ethanol in Africa due to the potential of recycling and reusing solid acid catalysts.
Cell wall configuration and ultrastructure of cellulose crystals in green seaweeds
Cellulose, 2021
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.
Optimization of Hydrolase Production (Dataset).pdf
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...
Optimization of Hydrolases Production (Dataset).pdf
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...
Conversion of cassava peels into bioethanol using the OSTEP approach
Biomass Conversion and Biorefinery, 2022
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.
The Production of Pozzolana Using High Calorific Waste
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.
Effect of Different Sets of Pleurotus ostreatus and Aspergillus niger Hydrolysis of Cassava Peelings on Bioethanol Yield
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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