?-glycosidase of the GH3 family produced by filamentous fungus isolated from the intestine of Nausitora fusticula (Bivalvia: Teredinidae) / ?-glicosidase da família GH3 produzida por fungo filamentoso isolado do intestino de Nausitora fusticula (Bivalvia: Teredinidae)

Abstract

Cellulolytic enzymes are those that are able to break down cellulose into its monomeric component, glucose. This group of enzymes is divided into endoglucanases that act inside the cellulosic fiber, exoglucanases that act on the ends of the chains, and ?-glucosidases that act on endo and exoglucanase products, cellobiose, releasing glucose as the final product. The main producers of these enzymes are filamentous fungi and the search for new microbial sources of these enzymes is essential for research involving the production of bioethanol, to improve the efficiency of this process. The objective of this work was to investigate the production of the cellulolytic complex in a lineage of filamentous fungus, isolated from the intestine of specimens of the teredo species Nausitora fusticula, to characterize some biochemical properties of the isolated enzymes and partially purify them to obtain a cellulolytic extract. From the digestive system of N. fusticula, were isolated fungi good producers of cellulases, which were classified as better producers through enzyme index tests. One specie stood out in the production of the three investigated enzymes, and this was grown in a medium containing carboxymethylcellulose and sugarcane bagasse as substrates for obtaining enzymatic extracts. Cultures with sugarcane bagasse produced a greater amount of cellulases. The production kinetics of these enzymes was evaluated in cultures of up to six days. The temperature and optimum pH of each enzyme was verified, as well as their stability at a temperature of 52º C. The enzymes were partially purified by the ion exchange technique and analyzed by mass spectrometry. The enzyme ?-glycosidase produced showed high similarity with ?-glycosidases of the GH3 family produced by the fungal species Bipolaris sorokiniana. The morphological characteristics of the isolated strain of N. fusticula intestine were very similar to those described for the species B. sorokiniana, which strongly suggests the correlation of these species and consequently the enzymes produced by them