CONSTRUCTION OF NEW .ALPHA.-GALACTOSIDASE PRODUCING YEAST STRAINS AND THE INDUSTRIAL APPLICATION OF THESE STRAINS

摘要

New Saccharomyces cerevisiae yeast strains having .alpha.-galactosidase gene (MEL+) transferred by recombinant DNA methodsare disclosed. The new strains produce more .alpha.-galactosidase thannaturally .alpha.-galactosidase producing yeast strains. Methods formarking yeast strains and for producing stable transformants ofyeasts are also disclosed. Baker's and distiller's yeastsproducing .alpha.-galactosidase are used in the correspondingindustries, due to their ability to utilize the raffinose presentin molasses, which results in greater yield of yeast (or ethanol)and reduction or elimination of the costs associated withbiological oxygen demand (B.O.D.) in the effluent from factories.The improved ability of brewer's yeasts to produce .alpha.-galactosidaseprovides a sensitive method for monitoring pasteurization of beer.