Excellent waste biomass-degrading performance of Trichoderma asperellum T-1 during submerged fermentation

The random disposal and incineration of agricultural residues cause resources waste and environmental pollution. The potential of waste biomass for the production of alternative liquid fuels is increasing and the bioconversion of lignocellulose to fermentable monomeric sugars is essential for second-generation biofuel production. Here, natural and pretreated switch grass or rice straw were fermented by both Trichoderma asperellum T-1 and Trichoderma reesei QM6a, with the fermentation results highlighted the potential of T. asperellum T-1 in the degradation of natural waste lignocellulosic materials. In fermenting different substrates, the filter paper activity, β-glucosidase activity, xylanase activity and carboxymethyl cellulase activity of T-1 can respectively reach 1.88, 8.00, 7.15 and 20.52 times that of QM6a. Although acid pretreatment could improve the enzyme activities of both T-1 and QM6a, its effect on T-1 was much smaller than that on QM6a. Moreover, strain T-1 fermented the natural rice straw better than the pretreated rice straw. Therefore, T-1 is considered to be more suitable for the degradation of natural biomass, especially for the degradation of rice straw. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and scanning electron microscopy (SEM) showed that the cellulase series secreted by T. asperellum T-1 was more abundant, and its substrate deconstruction ability was stronger than T. reesei QM6a. All these results suggest the potential of T. asperellum T-1 in the degradation of natural waste lignocellulosic material, with practical benefits in terms of cost and pollution reduction.