Lignocellulosic materials are promising alternative feedstocks for bioethanol production. However, the recalcitrant nature of lignocellulosic biomass necessitates an efficient pretreatment pretreatment step to improve the yield of fermentable sugars and maximizing the enzymatic hydrolysis efficiency. Microwave pretreatment may be a good alternative as it can reduce the pretreatment time and improve the enzymatic activity during hydrolysis. The overall goal of this paper is to expand the current state of knowledge on microwave-based pretreatment of lignocellulosic biomass and microwave assisted enzymatic reaction or Microwave Irradiation-Enzyme Coupling Catalysis (MIECC). In the present study, a comparison of microwave assisted alkali pretreatment was tried using Oil Palm empty fruit bunch. The microwave assisted alkali pretreatment of EFB using NaOH, significantly improved the enzymatic saccharification of EFB by removing more lignin and hemicellulose and increasing its accessibility to hydrolytic enzymes. The results showed that the optimum pretreatment condition was 3% (w/v) NaOH at 180 W for 12 minutes with the optimum component loss of lignin and holocellulose of about 74% and 24.5% respectively. The subsequent enzymatic saccharification of EFB pretreated by microwave assisted NaOH (3% w/v); resulted in 411 mg of reducing sugar per gram EFB at cellulose enzyme dosage of 20 FPU. The overall enhancement by the microwave treatment during the microwave assisted alkali pretreatment and microwave assisted enzymatic hydrolysis was 5.8 fold. The present study has highlighted the importance of well controlled microwave assisted enzymatic reaction to enhance the overall reaction rate of the process.

Worldwide efforts are being made to increase the use of renewable energy in order to reduce the emission of greenhouse gases. Africa is blessed with abundant resources of fossil fuels as well as renewable energy resources. Yet the continent, especially sub-Saharan Africa, is afflicted with power crisis. For example, in Nigeria, erratic electricity supplies will persist unless the government diversifies her energy sources and adopt new technologies available in the electricity generation sector. International Renewable Energy Agency (IRENA) has called for promotion of increased utilization of the continent's vast renewable energy resources to accelerate development. This review examines the perspective of renewable energy from biomass as an important strategy for a sustainable development in Nigeria. The paper also addresses the use of pyrolysis technology--an efficient thermo-chemical process for energy applications. However, the study presents on applications either to replace fossil fuel in an existing diesel engine-based power generation system or to generate electricity using a gas engine. The work also presented herein addresses the use of industrial-and non-industrial-derived biomass residues for energy purposes with specific example on solid palm oil residues in Nigeria. The current status of pyrolysis technology and its potential for commercial application for bio-fuel production using microwave-assisted pyrolysis in Nigeria are presented. This study will extensively review the recent work on microwave-assisted technology applied to the pyrolysis process. It is estimated that electrical power generation potential at about 500 MW can be obtained by using only the available residues from oil palm industry in Nigeria. This potential can be increased 10-fold with more emphasis on expansion and modernization of oil palm industry in Nigeria. This will benefit in terms of higher revenue from the palm oil export as well as higher renewable energy generation from its biomass residue using the microwave-assisted pyrolysis technology.

Problem statement: Environmental issues such as global warming and recent events throughout the world, including the shortage of petroleum crude oil, the sharp increase in the cost of oil and the political instability of some crude oil producing countries, have demonstrated the vulnerability of the present sources for liquid fuel. These situations have created great demand for ethanol from fermentation process as green fuel. A main challenge in producing the ethanol is the production cost. A rapid and economical single step fermentation process for reliable production of bioethanol was studied by co-culturing commercialized ragi tapai with Saccharomyces cerevisae using raw sago starch. Approach: Enzymatic hydrolysis of sago starch by various amylolytic enzymes was investigated to reveal the potential coupling mechanism of Microwave Irradiation-Enzyme Coupling Catalysis (MIECC). Results: It was shown that enzymatic hydrolysis of starch using typical enzymes may successfully be carried out at microwave condition. The MIECC resulted in increasing initial reaction rate by about 2 times. The results testify on specific activation of enzymes by microwaves and prove the existence of non-thermal effect in microwave assisted reactions. Low power microwave irradiation (80W) does not increase the temperature beyond 40 o C and hence denaturation of the enzyme is avoided. The maximum ethanol fermentation efficiency was achieved (97.7% of the theoretical value) using 100 g L −1 sago starch concentration. The microwave assisted process improved the yield of ethanol by 45.5% compared to the non-microwave process. Among the other advantages of co-culturing of ragi tapai with S. cerevisiae is the enhancement of ethanol production and prevention of the inhibitory effect of reducing sugars on amylolytic activity and the reaction could be completed within 32±1 h. Conclusion: The present study have demonstrated the ability of using cheaply and readily ragi tapai for conversion of starch to glucose and the utilization of sago starch as a feed stock, which is cheaper than other starches like corn and potato. The present study has highlighted the importance of well controlled microwave assisted enzymatic reaction to enhance the overall reaction rate of the process.

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