Biochemical characterization of a metagenomic cellulase from family 5 and determination of biotechnological application

Abstract

The development of renewable sources of energy is mainly motivated by the projection of oil reserves depletion and climate change caused by combustion of fossil fuels. In this context, lignocellulosic biomass is a promising renewable source of energy because of its wide availability and low cost. Therefore, it is necessary that the polysaccharides comprised in the plant cell wall are depolymerized into its monomeric units, to be employed in the stages of fermentation. The application of enzymatic hydrolysis to the release of sugars from plant cell wall presents some difficulties, mainly associated to the high costs and low yields of the processes. In this sense, metagenomic has been successfully applied in the identification of new glycolytic enzymes in the genome of so-called "not cultured microorganisms." The aim of this work is to conduct the biochemical characterization of a cellulase belonging to glycosyl hydrolase family 5, named CelE2, which was identified after functional screening of a metagenomic library derived from soil. After cloning, heterologous expression and protein purification, CelE2 will be tested to determine the preferential substrates of action as well as the effect of pH and temperature on the activity of the enzyme. Furthermore, the kinetic parameters, thermal stability, and the effects of ions will be evaluated, as well as, CelE2 enzymatic activity in complex substrates such as sugarcane bagasse. Thus, it will be possible to determine the potential application of CelE2 in the processes of conversion of plant biomass to the production of bioproducts.