Beta-frutofuranosidase de aspergillus versicolor utilizando fonte de carbono alternativa: produção, purificação e caracterização enzimática

Abstract

Extracellular β-fructofuranosidase production from Aspergillus versicolor was significantly increased after optimization of culture conditions by Central Composite Rotational Design (CCRD). The variables studied were apple pomace, initial pH and cultivation time, and in response to enzymatic activity of β-fructofuranosidase. The maximum yield of β-fructofuranosidase was obtained when the fungus was grown for 12 days in medium supplemented with 3% (w/v) apple pomace as carbon source and the initial medium pH 7.0. In the purification procedure, the extracellular crude extract of A. versicolor was precipitated with ammonium sulfate 75%, and applied to the ion exchange chromatography DEAE-Sephadex, which resulted in two peaks of enzyme activities, named β-fructofuranosidase-I and II. The β-frutofuranosidase- I exhibited optimum temperature and pH of 55°C and 6.0, respectively. The enzyme was stable at temperatures from 40 to 60°C and the pH in a range from 3.0 to 6.0. The activity of β-fructofuranosidase-I was increased in the presence of the Fe2+ ion, and inhibited by Hg2+. The kinetic parameters Vmax and Km with sucrose as substrate were 26.71 mm and 56.980 μmol.min-1, respectively. These biochemical characteristics of the β-fructofuranosidase demonstrate the potential application of this enzyme in the ethanol production industry, which requires high temperature stability and acidic pH.