Application of enzyme preparations in the treatment of sawdust spent mushrooms substrate by Protaetia brevitarsis larvae

Abstract With the development of an edible mushroom industry, the efficient recycling and utilization of the by-product, known as spent mushroom substrate (SMS) has attracted wide attention. Sawdust SMS has the highest output and is the most difficult to use. Converting sawdust SMS using Protaetia brevitarsis larvae (PBL) is a recyclable and high-value strategy. However, PBL feeding on different sawdust SMS varies greatly, and even refuse to feed. Therefore, in order to make better use of PBL feeding SMS, realize the recycling of resources. We screened out inoculant for sawdust SMS fermentation from four commercial inoculants by comparing the PBL feed intake, weight gain, and growth condition. Then, exogenous endoglucanase was added to the fermented sample to explore its effect on the feeding and degradation of lignocellulose. The results showed that (1) cellulases was the most suitable for fermenting sawdust SMS, and (2) adding appropriate exogenous endoglucanase during feeding could increase PBL weight gain, activities of cellulases and xylanase in the intestine, and did not affect the degradation of lignocellulose. In short, the best time to use enzyme preparation to speed up the feeding of sawdust SMS is when fermented.