Library generation for biomass-conversion enzymes from soil metagenome

Abstract

The gradual shift from petroleum to renewable biomass resources is generally seen as an important contribution to the development of a sustainable industrial society and the effective management of green house emissions. Lignocellulosic materials, such as agricultural and forestry residues, are an abundant and low-cost source of stored energy in the biosphere. Thus, biomass conversion into feedstock sugars has moved towards the forefront of the biofuel industry. However, the saccharification of plant biomass is a complicated and lengthy process, mainly due to the inherent recalcitrance and the complex heterogeneity of the polymers comprising plant cell walls. Lignocellulosic biomass must go through an intensive pretreatment step, after which enzymes are used to break down the polysaccharides biomass into simple sugar suitable for fermentation and ethanol production. Likewise, enzymatic conversion of cellulose and hemicellulose into simple sugar is also a demanding task, where a consortium of enzymes is needed for complete saccharification of these polysaccharides. Aiming at the entire exploitation of the plant cell wall polysaccharides, as an environmentally renewable energy source, an extensive repertoire of hydrolytic enzymes would play a major role for biofuel production. The objective of this proposal is the generation of a toolkit of lignocellulolytic enzymes with a wide range of biotechnological applications, including their use as players for the development of strategies for second generation ethanol production. The prospection of these enzymes will be done from soil metagenome, which contemplates a pioneering strategy towards the prospection of biomass conversion enzymes from microorganisms not conventionally cultivable. Additionally, this study may intensively contribute to the development of the field of bioenergy by improving techniques in rapid detection of hydrolysis using capillary electrophoresis and implementing heterologous gene expression in filamentous fungi. (AU)