Ethanol production from sugi pulp under simultaneous saccharification and fermentation using a cocktail enzyme of T. reesei and A. tubingensis produced by solid-state fermentation

The process of solid-state fermentation was used to produce a cocktail enzyme of Trichoderma reesei ATCC 66587 and Aspergillus tubingensis KRCF 700-33. Wheat bran, corncob, and sugi pulp were supplemented with ammonium sulfate as an enzyme-producing medium using T. reesei and A. tubingensis. The corncob blend ratio, duration of incubation, and ammonium sulfate concentration were optimized for enhancing cellulase production from T. reesei using a Box-Behnken design. Filter paper degrading activity more than tripled when T. reesei was grown in the optimized medium, as compared with the initial medium. The highest activity of 4.03 FPU/ml (about 29 FPU/g of dry material) was obtained with a cocktail enzyme having a 25 % content of A. tubingensis and 75 % of T. reesei. The sugi pulp was then fermented to ethanol with the cocktail enzyme and thermotolerant yeast (Saccharomyces cerevisiae BA-11) under simultaneous saccharification and fermentation (SSF) at 40 °C. An ethanol concentration of 4.48 % (w/v) was achieved using the cocktail enzyme (4 FPU/g-pulp) that was produced on-site with a substrate loading level of 12.5 wt %, which achieved an ethanol yield of 76 % after 72 h.