The optimized co-cultivation system of Penicillium oxalicum 16 and Trichoderma reesei RUT-C30 achieved a high yield of hydrolase applied in second-generation bioethanol production.

Abstract A low-level secretion of hydrolase and low conversion efficiency represent two major challenges in production of second-generation bioethanol. In the study, the co-cultivation system of Penicillium oxalicum 16 and Trichoderma reesei RUT-C30 optimized by response surface methodology under solid state fermentation produced 38.0 IU/gds, 352.9 IU/gds, 713.2 IU/gds, 15.7 IU/gds and 188.6 IU/gds for FPase, xylanase, amylase, cellobiohydrolase and β-1, 4-glucosidase, respectively, which was corresponding to 4.2 fold, 2.9 fold, 2.03 fold, 1.08 fold and 1.96 fold higher than that without optimization. Moreover, unpretreated wheat bran which was hydrolyzed by the optimized co-cultivation system and fermented by Saccharomyces cerevisiae UV-20 was converted into 26.8 g/L ethanol corresponding to 98.41% of the conversion rate, and produced much more ethanol than milled rice straw. The study provided a feasible method which can enhance hydrolase yield and very efficiently produce second-generation bioethanol. Highlights • PO16 and RUT-C30 were co-cultured for the first time under SSF. • Co-48 optimized by RSM generated a significant enhancement of the hydrolase yield. • Unpretreated WB was completely hydrolyzed by the optimized Co-48. • Unpretreated WB was almost completely turned into ethanol. [ABSTRACT FROM AUTHOR]