%0 Journal Article
%T Microwave Assisted Alkali Pretreatment of Rice Straw for Enhancing Enzymatic Digestibility
%A Renu Singh
%A Sapna Tiwari
%A Monika Srivastava
%A Ashish Shukla
%J Journal of Energy
%D 2014
%R 10.1155/2014/483813
%X Rapid industrialization, increasing energy demand, and climate change are the conditions that forced the researchers to develop a clean, efficient, renewable, and sustainable source of energy which has a potential to replace fossil fuels. Ethanol is one of the attractive and suitable renewable energy resources. In present study, effectiveness of microwave pretreatment in combination with sodium hydroxide (NaOH) for increasing enzymatic hydrolysis of rice straw has been investigated and under optimum conditions obtained a maximum reducing sugar (1334.79£¿¦Ìg/mL) through microwave assisted NaOH pretreatment. Chemical composition analysis and scanning electron microscope (SEM) images showed that the removal of lignin, hemicellulose, and silicon content is more in microwave assisted NaOH pretreatment than the blank sample. X-ray diffraction (XRD) analysis revealed that the crystallinity index of rice straw treated with microwave assisted alkali (54.55%) is significantly high as compared to the blank (49.07%). Hence, the present study proves that microwave assisted alkali pretreatment can effectively enhance enzymatic digestibility of rice straw and it is feasible to convert rice straw for bioethanol production. 1. Introduction In recent times, due to increase in concerns for climate change and greenhouse gas emissions, research work has been inclined towards the development of sustainable and renewable energy resources. The atmospheric CO2 levels increased from ~275 to ~380£¿ppm [1]. From renewable resources, ethanol has been of great interest as an alternative fuel or oxygenate additive for fossil fuels. In 2005 and 2006, worldwide production capacity of ethanol was about 45 and 49 billion litres, respectively, and the total projected demand in 2015 is over 115 billion litres [2]. Lignocellulosic materials are abundant, cheap, and renewable and may be used as a substrate for ethanol production through microbial intervention [3]. Cereal straws are the most abundant resource which can serve as a potential feedstock for the production of biofuel [4]. Rice contains 23% straw of its total weight. Usually, farmers burnt the rice straw left on the field in order to clear the field for the next crop. In India, open-field burning of rice straw contributes up to 0.05% of total GHG emissions [5]. Use of rice straw for bioethanol production not only provides a renewable fuel but also prevents climate change. Rice straw is mainly composed of cellulose, hemicellulose, lignin, silica, and ash contents. Conversion of rice straw to fermentable sugar is a very complicated
%U http://www.hindawi.com/journals/jen/2014/483813/