HETEROLOGOUS EXPRESSION OF A CANDIDA-MOLISCHIANA ANTHOCYANIN-BETA-GLUCOSIDASE IN A WINE YEAST-STRAIN

A recombinant wine yeast strain expressing the Candida molischiana bgl n gene encoding a beta-glucosidase/anthocyanase under the control of t he Saccharomyces cerevisiae actin gene promoter has been constructed. The corresponding protein, BGLN, was mainly located on the cell wall. BGLN was purified in a single chromotagraphic step, and different phys icochemical and kinetic properties have been determined. BGLN showed m aximum activity against the artificial substrate p-nitrophenyl beta-D- glucopyranoside. It also hydrolyzed salicin, p-nitrophenyl beta-D-xylo side, cellobiose, and arbutin to a lesser extent. Fructose and SO2 did not affect enzyme activity, which was activated by ethanol, while glu cose was a strong competitive inhibitor. The purified BGLN showed a no vel anthocyanase decolorizing capability on red wines. This anthocyana se activity was readily observed during microvinification experiments. However, the physicochemical characteristics of the wines obtained wi th the recombinant wine yeast strain were indistinguishable from those obtained with the parental strain.