Enzymatic Saccharification and L-lactic Acid Fermentation of Corn Stover Pretreated with Liquid Hot Water by Rhizopus oryzae

Corn stover was pretreated with liquid hot water (LHW) to enhance its enzymatic hydrolysis and L-lactic fermentation. The cellulose conversion rate and L-lactic acid concentration were used to evaluate LHW pretreatment performance. Results showed that the optimum conditions for the LHW pretreatment of corn stover are a reaction temperature of 190 C for 20 min and a solid-to-liquid ratio of 1:10. The cellulase loading was 30 filter paper units per gram of oven-dried, water-insoluble solid. These conditions resulted in 92.3% conversion of cellulose to glucose. Sequential hydrolysis and fermentation using pretreated water-insoluble solid (WIS) produced an L-lactic acid concentration of 45 g/L. This study indicated that LHW pretreatment of corn stover is a suitable method for achieving high cellulose conversion and L-lactic acid concentration.