Sequential fermentation of organosolv pretreated corn stover for improved cellulose hydrolysis and bioethanol yield

In this study, organosolv pretreatment of corn stover using 40% acetic acid was investigated for its amenability for enzymatic saccharification and bioethanol production. The pretreated corn stover resulted in 63.4±1.7% solids, 46.4±2.5% hemicellulose and 53.7±2.1% cellulose recoveries with 84.6% delignification. The reducing sugars of 0.107g/gds (107/Kg) released during pretreatment can be fermented to produce 0.125ml/gds (125ml/Kg) bioethanol. The saccharification of pretreated biomass under optimized conditions released 0.395g/gds reducing sugars, which upon subsequent fermentation by Saccharomyces cerevisiae and Pachysolen tannophilus produced 0.112g/gds (140ml/Kg) ethanol, with 66.54% fermentation efficiency and 33.9% ethanol yield (YPS), under separate hydrolysis and fermentation (SHF) conditions. The net price for the bioconversion of 1Kg corn stover for bioethanol (265 ml) production was calculated to be Rs. 144.3/L of ethanol. This price is high being calculated on laboratory scale (1Kg) and will decrease substantially upon upscaling.