Produção, purificação e caracterização de uma celulase termostável e halotolerante de uma linhagem marinha de Bacillus sp.

Abstract

The current demand for environment-friendly renewable energy sources has driven the search for alternatives capable of replacing the use of fossil fuels. One of the most promising innovations to positively impact the world energy scenario is the second-generation bioethanol production (B2G) from reducing sugars derived from enzymatic degradation of lignocellulosic material that is ordinarily discarded at agroindustrial processes. In this work, a salt-tolerant cellulase secreted by a marine Bacillus sp. SR22 strain with wide resistance to temperature and pH was isolated and characterized. The 37.35 kDa endoglucanase named as Bc22Cel was purified by ammonium sulphate precipitation, gel filtration chromatography and extraction from the gel after non-reducing sodium dodecylsufate-polyacrylamide gel electrophoresis. The optimal pH value and temperature of Bc22Cel were 6.5 and 60 °C, respectively. The purified Bc22Cel showed a considerable halophilic property being able to maintain more than 70% of residual activity even when pre-incubated with 1.5 M NaCl for 1 hour. Kinetic analysis of purified enzyme showed the Km and Vmax to be 0,3953 nmol ml-1 and 0,0167 μmol ml-1 min-1, respectively. Taking together, the present data indicates the Bc22Cel as a potential and useful candidate for industrial applications.