Spent brewery grains as substrate for the production of cellulases by Trichoderma reesei QM9414

Abstract

The cellulolytic fungus Trichoderma reesei QM9414 can be cultivated on spent brewery grains for the production of cellulases. The levels of the cellulase components endoglucanase and exoglucanase synthesized, and the complexes filter paper cellulase and grain-hydrolizing cellulase synthesized by the organism on spent grains were as high as 287, 182, 187, and 449 units per g available cellulose, respectively. Scaling up the spent grains fermentation system by up to 40-fold (200 g dry substrate/tray) demonstrated that cellulase production was comparable to laboratory scale (5 g dry substrate/flask) yields. Cultivation of the fungus was feasible on spent grains without pretreatment or further adjustment, although the enzyme yield was somewhat lower than that on dried grains moistened with water or Trichoderma medium. This suggested the possible reutilization of spent grains, with minimal pretreatment, in the cultivation of T. reesei QM9414 for cellulase synthesis and for future incorporation into animal feed.