Construction of new alpha-galactosidase producing yeast strains and the industrial application of these strains.

摘要

Described are new Saccharomyces cerevisiae yeast strains transformed withan alpha -galactosidase gene (MEL<+>) using recombinant DNA methods. Baker's and distiller's yeasts producing alpha -galactosidase are used in the corresponding industry because they are able to utilize the raffinose contained in molasses. This results in a greater yield of yeast (or ethanol) and in reduction or elimination of the costs associated with the biological oxygen demand (B.O.D.) in the effluent of factories. As a result of the improved ability of brewer's yeasts to produce alpha -galactosidase a sensitive method for monitoring pasteurization of beer is provided. The new yeast strains prepared by using recombinant DNA methods produce more alpha -galactosidase than naturally occurring alpha -galactosidase producing yeast strains. Also described are methods for marking yeast strains and for producing stable transformants of yeasts.