Structural studies and functional properties of xyloglucanases and lichenases: applications on hydrolysis of lignocellulosic biomass

Abstract

The lignocellulosic biomass consists of three main components: cellulose, hemicellulose and lignin. Its degradation and conversion are attractive in biotechnology. It is known that the carbohydrate polymers of the plant cell wall are not composed of randomly attached monosaccharides, but by polymers with fine and very stringent structures. This complex structure suggests that the cell wall could have a glycomic code, which would be the last barrier to efficient hydrolysis of the wall. However, cell wall fractionation is not a simple process, however, microbial enzymes may be the solution. Xyloglucan is the predominant hemicellulose of the primary cell wall of higher plants and plays a key role during cell growth and differentiation. In this way, the enzymes that cleave this polymer, the xyloglucanases, have great utility in the degradation and conversion of the lignocellulosic biomass. ’-glucans are the major linear polysaccharides in the cell wall endosperm of cereals. Its degradation is catalyzed by the ²-glucanases, among them the lichenases. The production of bioethanol is a process that has a relatively high cost. In this sense, fungi were the microorganisms chosen in this study, because they have an adaptation to environmental niches, which encourages the production of several enzymes potentially useful in industrial applications. The present work has as an innovative objective to carry out the prospection, production, biochemical characterization and molecular modeling of xyloglucanases and lichenses produced by filamentous fungi with potential for industrial application. These enzymes will be part of enzymatic cocktails that aim at the degradation of lignocellulosic material from sugar cane and other agricultural residues. This proposal is linked to the thematic project INCT of Bioethanol, coordinated by Prof. Dr. Marcos Silveira Buckeridge and already approved by FAPESP/CNPq in early 2017. (AU)