MUTANTS PRODUCING HIGH-CONCENTRATIONS OF THE FLAVOR COMPONENTS ACTIVE AMYLALCOHOL AND NORMAL PROPANOL IN SACCHAROMYCES-CEREVISIAE

Mutants resistant to the isoleucine analogue DL-thiaisoleucine (TIL) which produced large amounts of the flavor components active amylalcohol and normal propanol were isolated from sake, and baker's and laboratory yeasts Saccharomyces cerevisiae. These mutants had threonine deaminase (EC 4.2.1.16) with decreased feedback sensitivity to L-isoleucine and accumulated a high concentration of isoleucine as well as these higher alcohols. Genetic analysis using a laboratory strain revealed that the mutation for increased production of active amylalcohol and normal propanol was controlled by a single dominant gene, and evidence was found for linkage between TIL-resistance and the increased production ability of these higher alcohols. Sake and bread made with the mutants contained more of these components and had enhanced flavor.