Bioethanol and paddy straw? From 1979 until 1983, the Rice Research Board has funded several research projects to find economic uses for paddy straw (rice straw) with the principal objective to reduce or eliminate rice straw burning as the means for disposal (California Rice Research Board, n.d.). These burning activities of the rice straw that lead to the air pollution that has been practically done in some countries especially after the harvesting process of the vegetation not only surges the emissions of greenhouse gases but also affect human and soil health. On top of that, the search for sustainable and economically viable alternative source of biofuel has become vital to the global. One of the biofuels that have been produced for a decade is bioethanol.
The production of bioethanol as the alternative renewable source is focused on the usage of the lignocellulosic biomass of plant residues that are not food resources. This bioethanol production from the biomass has been used as an additive medium in fuels in some countries and also as an export product for many years. According to the Biofuel Organization of UK (2010) has stated that United States is the highest bioethanol-producing country in the world (40 billion litres) followed with Brazil (25 billion for litres), China (3 billion for litres), Canada (2 billion litres), India and France (1 billion litres), Germany (750 million litres) and Australia (500 million litres).The major utilization of plants residues that have been used for the production of bioethanol is obtained from the feedstock of paddy, wheat, corn, sugar cane and sugar beet. The rice straw from paddy which is one of the abundant lignocellulosic waste materials in the world that have been annually produced about 731 million tonnes and can potentially produce 205 billion litres bioethanol per year is made up of complex carbohydrates (Karimi, Emtiaz & Taherzadeh, 2005). The component of lignocellulose is made up of three structural components which are cellulose (glucan), hemicellulose, and klason lignin. The chemical composition of the rice straw predominantly contains 32-47% of cellulose, 19-27% of hemicellulose, 5-24% of lignin and 10-17% of ash (silica) content (Binod et al.