Microbial delignification of corn stover by Ceriporiopsis subvermispora for improving cellulose digestibility

Delignification of corn stover by the white rot fungus Ceriporiopsis subvermispora in solid-state cultivation was evaluated for improving subsequent enzymatic hydrolysis. The results showed that C. subvermispora selectively degraded lignin by as much as 39.2% while the cellulose loss was less than 5% during 42 d of cultivation. However, hemicellulose loss of up to 27.0% was concomitant with the lignin degradation. Ligninolytic enzymes, MnP and laccase, were detected during degradation of corn stover by C. subvermispora. For major hydrolytic enzymes, xylanase was the only enzyme detected. The enzymatic hydrolysis yield of corn stover delignified by C. subvermispora was remarkably improved, reaching about 57–67% overall glucose yield after 18–42 d of pretreatment, while the glucose yield of the untreated was only 22%. A higher overall glucose yield of about 72% was obtained when the enzymatic hydrolysis of the 18 d treated corn stover was supplemented with an accessory xylanase/cellulase enzyme complex.