Date of Publication :14th December 2016

Abstract: Due to increase in population and industrialization, all over the globe the demand for fossil based fuel is constantly increasing. This increase in demand for non-renewable fossil based fuel is exhausting the reservoirs of oil as well as possesses severe threats to environment. Thus energy sector have shifted its focus from non-renewable fossil based fuel to renewable biofuels like biogas, bioethanol, biodiesel, etc., contributing towards sustainable development and overcome the threats to environment. Among these biofuels, bioethanol is substituting source of energy receiving special attention over the globe due to exhaustion of non-renewable fossil fuels and has some significant advantages such as its capability to replace gasoline, to achieve the carbon emission goals under Kyoto Protocol and can be used as transportation fuel with minimal or no modifications in the existing vehicular engines. This bioethanol is produced using lignocellulosic materials and biomass like municipal solid waste, crops, etc. But crops cannot meet the global requirements of bioethanol production considering food v/s fuel debate. So, the lignocellulosic substances such as agricultural wastes, kitchen waste, municipal solid waste etc., are captivating raw material for bioethanol production. Agricultural wastes and kitchen wastes are not only cost effective but are also renewable and ample in quantity. Bioethanol from lignocellulosic material could be a promising technology though the process has several provocations and limitations such as handling and transport of the biomass and coherent pre-treatment methods for total delignification of lignocellulosic materials. Concentrations of fermentable sugars after enzymatic saccharification or enzymatic hydrolysis can be increased by considering appropriate pre-treatment methods, also improving the efficiency of the process. Converting glucose as well as xylose to bio-ethanol needs some new technologies, to make the whole process cost effective. This paper reviews various pre-treatment methods available for lignocellulosic materials to be further hydrolyzed and fermented to produce bioethanol.

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