Abordagem metagenômica para isolamento de uma nova celulase em restos culturais de arroz vermelho

Abstract

Red rice is practically unknown by most Brazilians, but in Paraíba as in other Northeastern states, it is highly cultivated and has great socioeconomic importance, cultivated mainly by small farmers. In agricultural activity, large quantities of cellulolytic materials are generated. This material is degraded by cellulolytic microorganisms, which hydrolyze and metabolise cellulose efficiently. There is a great commitment to the development of renewable alternatives to fossil fuels and one of these alternatives is second generation ethanol production, using enzymatic hydrolysis in vegetable biomass derivatives and subsequent fermentation. Microorganisms exhibit immense genetic diversity and play a variety of roles in maintaining ecosystems. One of these functions is the production of extracellular enzymes, which help in the degradation of organic matter. Cellulase is an enzyme that hydrolyzes cellulose by breaking the β-1,4 linkage. In the search for new non- cultured microorganisms, metagenomics appears as a tool that isolates DNA from environmental sources to identify enzymes with biotechnological potential. In this work, a gene encoding an endoglucanase was cloned from red rice culture residues using the metagenomic strategy. The amino acid identity between this gene and its nearest published congeners is less than 70%. The gene found has potential for use in the production of ethanol from cellulosic biomass (second generation ethanol).