Relation between Sugar Consumption and Bioethanol Production Potential in Lignocellulosic biomass

Bioethanol more appropriately termed as alternative transportation fuel play a key role in reducing the world dependence on fossil fuels. Bio-ethanol is an oxygenated fuel that contains 35% oxygen which reduces particulate and nitrogen oxides (NOx) emissions from combustion. Henceforth using bioethanol blended fuel for automobiles can significantly reduce petroleum use green house gas emission. Developing ethanol as fuel, beyond its current role as fuel oxygenates will require developing lignocellulosic biomass as a feedstock because of its availability and low cost. In present study Azolla, lignocellulosic biomass is used as a substrate as it is cheap and has cellulose content 15.19 +/- 1.35 % of its dry weight which can be converted into the fermentable sugar through biological pretreatment. This fermentable sugar is used by the fermenting microorganism i.e. Saccharomyces cerevisiae MTCC 4780 and through anaerobic oxidation converted into bioethanol. It has been found that there is co-relation among the fermentable sugar concentration and bioethanol production. As the concentration of reducing sugar is determined by the dinitrosalicylate method (DNS Assay), a relation among the value of DNS and the bioethanol production is established. In the present study maximum sugar consumption by Saccharomyces cerevisiae MTCC 4780 is 0.42 mg/ml which results in maximum bioethanol production 4.06% (w/v). As various parameters get optimized, the bioethanol production potential from the consumed sugar level is also enhanced and the maximum production which was obtained in presence of 1 ml 1% KCl solution is 5.20%.