Commercialization of 2G bioethanol as a transportation fuel for the sustainable energy, environment, and economic growth of India: theoretical and empirical assessment of bioethanol potential from agriculture crop residues

Determination of structural carbohydrates content of a lignocellulosic biomass is a preliminary step for the predictive analysis of its bioethanol potential. In this study, the annual agriculture crop residues like rice straw, wheat straw, corn stover, and sugarcane bagasse have been selected as lignocellulosic biomass, which contains about 59.6-61.4% structural carbohydrates. Based on the stoichiometry of glucose/xylose/arabinose, theoretical bioethanol yield is accounted to be 387 L/dry tons of lignocellulosic biomass. Moreover, empirical mode of bioethanol potential of selected agriculture crop residues has been evaluated by considering the biochemical conversion process developed by National Renewable Energy Laboratory (NREL). The process includes deacetylation, acid impregnation, pretreatment, enzymatic hydrolysis and fermentation. NREL performed pilot scale demonstrations runs and evaluated bioethanol yield per dry ton of lignocellulosic biomass. Moreover, NREL estimated the minimum ethanol selling price (MESP) by a process simulation software, Aspen plus, by considering the end-to-end process which includes capital investment, feedstock handling, biochemical conversion process, coproduct credit and wastewater treatment. Therefore, a pilot scale study of NREL has been opted for the empirical estimation of bioethanol potential of selected lignocellulosic biomass. As a result, about 295 L of bioethanol can be produced per dry ton of lignocellulosic biomass with a MESP of 0.56 US$/L.