Enzymatic oxidation of sugarcane bagasse: discovery, characterization and new application of oxidative enzymes active in carbohydrates, applied to the enhancement of a fungal cell factory

Abstract

Lignocellulosic biomass is an abundant source of polysaccharides that can be used as a renewable raw material to produce biofuels and other compounds. The conversion of these polysaccharides into fermentable sugars by enzymatic pathway still is a slow and expensive process, which a fast and efficient process still remains to be discovered. Until recently, the available commercial preparations had in your repertoire enzymes that the mechanism to hydrolyze components of lignocellulose were based in acid-base mechanism, which are not efficient to hydrolyze crystalline cellulose and lignin. Recently, proteins with oxidative mechanisms working as auxiliary enzymes acting directly on crystalline cellulose called LPMOs have been discovered. Since then, those enzymes were added to the available cocktails improving it’s efficient. Analyzing the secretome of thermophilic fungi Aspergillus niveus and Myceliophthora thermophila, we found that these organisms have different mechanisms (hydrolytic and oxidative, respectively), to degrade lignocellulosic materials. When the enzymatic extracts of the two species were mixed, the activity was increased five-fold. Therefore, this proposal will aim to 1) discover new oxidative protein working as electron acceptor obtained from the thermophilic fungus M. thermophila, participating in combination with acid-base mechanisms in the degradation of lignocellulosic biomass, followed for its biochemical and structural characterization; 2) Development of a multigenic expression system for A. nidulans and or A. niveus based in BioBricks combination and using Gibson Assembly method 3) combine the synergistic actions of oxidative and hydrolytic mechanism of two thermophilic microorganisms in a single cell with thermophilic characteristics and study the effects of this complementation during the time course of the lignocellulosic biomass breakdown. (AU)