Microbial pretreatment of corn stover with Ceriporiopsis subvermispora for enzymatic hydrolysis and ethanol production

The feasibility of concurrent wet storage and microbial pretreatment of corn stover with Ceriporiopsis subvermispora for ethanol production was investigated in this study. The effects of particle size (5–15 mm), moisture content (45–85%), pretreatment time (18–35 d), and temperature (4–37 °C) on lignin degradation and enzymatic hydrolysis yield were studied. The results showed that C. subvermispora selectively degraded lignin up to 31.59% with a limited cellulose loss of less than 6% during an 18-d pretreatment. When 5 mm corn stover was pretreated at 28 °C with 75% moisture content, overall glucose yields of 57.67%, 62.21%, and 66.61% were obtained with 18-, 28-, and 35-d microbial pretreated corn stover, respectively. For the above conditions, the highest overall ethanol yield of 57.80% was obtained with 35-d-pretreated corn stover. Enzymatic hydrolysis yield was highly related to the lignin removal during microbial pretreatment.