Bioconversion of cellulose and hemicellulose in corn cob into L-lactic acid and xylo-oligosaccharides

Abstract

With the banning of antibiotic chemical feed additives, multi-functional bioactive feed additives have been extensively sought after by the feed industry. In this study, low-cost and renewable corn cobs were treated with liquid hot water and converted into bioactive xylo-oligosaccharides and L-lactic acid after enzymatic hydrolysis, strain activation, and fermentation under mild conditions, which achieved a full utilization of cellulose and hemicellulose in corn cobs. Simultaneous saccharification fermentation after strain activation with enzymatic hydrolysate delivered the highest conversion rate of glucose to L-lactic acid (93.00 %) and yielded 17.38 g/L L-lactic acid and 2.68 g/L xylo-oligosaccharides. On this basis, batch-feeding fermentation resulted in a 78.03 % conversion rate of glucose to L-lactic acid, 18.99 g/L L-lactic acid, and 2.84 g/L xylo-oligosaccharides. This work not only provided a green and clean bioconversion strategy to produce multi-functional feed additives but can also boost the full utilization of renewable and cheap biomass resources.