Valorization of agricultural residues using Myceliophthora thermophila as a platform for production of lignocellulolytic enzymes for cellulose saccharification

Abstract

The use of lignocellulosic agricultural residues is emerging as a low-cost, sustainable, and eco-friendly approach for the production of microbial enzymes and other chemicals. In this study, the production of enzymes with lignocellulolytic potential and the secretome profile of the thermophilic fungus Myceliophthora thermophila were evaluated in solid-state cultivation on agricultural residues such as rice straw, soy straw, and wheat bran. In addition, the saccharification potential of the extracts was evaluated. The analysis of enzymatic activities (peptidase, lipase, amylase, CMCase, FPase, β-glucosidase, xylanase, pectinase, and laccase) and the 66 proteins identified in the secretome reinforced the hydrolytic and oxidative properties of the enzymatic lignocellulolytic arsenal produced by M. thermophila. The extracellular extract grown on rice straw obtained after 72 h of solid-state bioprocess achieved 46% saccharification of wheat bran substrate. Furthermore, the overall performance of the wheat bran extract (24 h) indicates the relevance of the CMCase, FPase and xylanase activities in saccharification processes. These results highlight the potential of M. thermophila as a platform for the production of enzymes with biotechnological potential, especially for lignocellulose degradation and cellulose saccharification. Solid-state bioprocess allows exploring agro-industrial residues, as a matrix and source of nutrients, for the enzyme production and emphasizes the possibility of adding value to agricultural waste. Moreover, the use of M. thermophila in solid-state bioprocesses can still be widely explored and optimized as a platform to scale up the production of cheapest fungal enzymes.