Enhanced formation of isoamyl alcohol inZygosaccharomyces rouxiidue to elimination of feedback inhibition of α-isopropylmalate synthase

Abstract

Mutants of the 'miso' yeast, Zygosaccharomyces rouxii, that produced a large amount of isoamyl alcohol, an important flavour in miso fermentation, were isolated from 5,5,5-trifluoro-DL-leucine-resistant mutants, an analogue of L-leucine. One of the mutants, M21-10, produced a three-fold higher level of isoamyl alcohol than the wild-type strain MY21 in miso fermentation. The activity of alpha-isopropylamalate synthase, one of the enzymes used for L-leucine synthesis, in the mutant M21-10 was not inhibited by the addition of L-leucine, a feedback inhibitor.

Genomic Exploration of the Hemiascomycetous Yeasts: 1. A set of yeast species for molecular evolution studies1

“…A second criterion was within each branch to give preference to species of industrial or biomedical interest, which could be used for subsequent functional studies or have already been the object of extensive genetic studies. Following these criteria, we have retained the following species Pichia angusta (also called Hansenula polymorpha ); K. lactis ; Yarrowia lipolytica and Zygosaccharomyces rouxii ; because they have been subjected to numerous genetic and molecular studies during the last 15 years and, as a direct consequence, are increasingly used for industrial purposes [37–43]. Saccharomyces bayanus (var.…”