An alkaline beta-glucosidase isolated from an olive brine strain of Wickerhamomyces anomalus.

摘要

An efficient beta-glucosidase ( betaG)-producing strain, Wickerhamomyces anomalus BS81, was isolated from naturally fermented olive brine and identified based on PCR/restriction fragment length polymorphism of the rDNA internal transcribed spacer and sequence analysis of the D1/D2 region of the 26S rRNA gene. The hydrolytic activity of the betaG had an optimum pH of 8.5 and an optimum temperature of 35 degrees C. The enzyme had high substrate specificity and high catalytic efficiency (K_m 0.99 mM, V_max 14 U g--1 of cells) for p-nitrophenyl- beta-D-glucopyranoside. The enzyme was activated by increasing concentrations of NaCl, with maximum activity at 150 g L--1 NaCl. Although betaGs have been purified and characterized from several other sources, the W. anomalus betaG is unique among betaGs because its relative maximum activity occurs at alkaline pH and 35 degrees C. Moreover, the yeast strain has esterase activity that acts synergistically with betaG to degrade oleuropein to debitter table olives and olive oil