The enzyme cocktail produced by endophytic Chaetomium globosum unlocks in situ production of sugars and shows great potential application in biorefinery

The approach producing sugars in situ has been considered as a viable way to significantly improve the economics of biorefinery. However, the implementation of in situ sugar production relies on highly efficient enzymes and their affordable, convenient production. We previously reported a lignocellulolytic enzyme cocktail (CG3) from Chaetomium globosum DX-THS3 which showed high hydrolysis performance for raw rice straw, revealing great potential to develop in situ production sugars. Herein, CG3 production process through solid-state fermentation was evaluated and verified at pilot scale in tray fermenters. By exploring solid-state inoculation, enzymatic performance comparable to conventional liquid-state inoculation was obtained in a shorter fermentation period (from 12 to 6 days). Compared to Cellic CTec 2, CG3 exhibited superior hydrolytic efficiency for various lignocellulosic biomasses, especially for untreated lignocellulose. Pretreated agricultural wastes hydrolyzed with CG3 high-efficiently yielded glucose (0.35–0.40 g/g dry biomass). Additionally, bioethanol production from Saccharomyces cerevisiae using CG3-generated sugars reached 41.0–52.9 g/L without detoxification. Overall, our study presents a promising enzyme cocktail for saccharifying lignocellulosic biomass and suggests an integrated approach for in situ enzyme and sugar production.