Saccharification of alkali treated biomass of Kans grass contributes higher sugar in contrast to acid treated biomass

Abstract

Economical production of biofuel is prerequisite to depletion of fossil fuel. In recent years, biomass of numerous food crops was used as a feedstock for bioethanol production. Unfortunately, due to limited availability as well as confliction with food, these sources may hold back for continuous production of bioethanol. Therefore, in the present study a waste land crop "Kans grass" was utilized as feedstock for microbial production of bio-ethanol. The Kans grass biomass obtained after NaOH pretreatment at optimum conditions (in term of lignin removal) was subjected to enzymatic saccharification by using crude enzyme (obtained from Trichoderma reesei) to total reducing sugars (TRSs), which was further fermented for bioethanol production using yeast strains. Different time (30, 60, 90 and 120min), concentrations of NaOH (0.5%, 1%, 1.5% and 2%) as well as temperatures (100, 110 and 120°C) were used for pretreatment study. At 120°C, approximately more than 50% of delignification was observed. Moreover, subsequent enzymatic saccharification contributed 350mgg-1 dry biomass of total reducing sugar (TRS) production. Interestingly, TRS was approx. fivefold higher than enzymatic saccharification of acid pretreated biomass (69.08mgg-1) as reported previously (Kataria et al., 2011) and fermentation of enzymatic hydrolysate using microbes resulted in the 0.44-0.46gg-1 ethanol yield which is a high yield when compared to the other existing literature. Another advantage of alkali pre-treatment was without production of toxic compounds in comparison to acid pre-treatment method. In conclusion, Kans grass was shown as potential feedstock for biofuel production via alkali and enzymatic saccharification in contrast to acid pre-treatment. © 2013 Elsevier B.V.