Genetic and molecular basis of the aroma production in S. kudriavzevii, S. uvarum and S. cerevisiae

Abstract

The species of the genus Saccharomyces, S. kudriavzevii and S. uvarum revealed significant differences during the formation of fermentative aroma as compared to S. cerevisiae. The main goal of this PhD thesis was to obtain a deeper fundamental understanding of the molecular aspects behind these differences. First part of the thesis describes observed differences among Saccharomyces kudriavzevii and Saccharomyces uvarum during the production of aroma-active higher alcohols and acetate esters using their amino acidic precursors comparing to Saccharomyces cerevisiae. Subsequent in silico comparative analysis of the enzymes involved in the branched-chain amino acids catabolism in S. cerevesiae, S. kudriavzevii and S. uvarum released ARO10, ATF1 and ATF2 as the candidates for further experiments. The heterologous expression of the individual ARO10, ATF1 and ATF2 alleles in a host S. cerevisiae resulted in the enhanced production of several higher alcohols and acetate esters. All together the data described and discussed in this thesis indicate that the amino acid variations observed between the decarboxylases encoded by the orthologues ARO10 genes and between the AATases encoded by the orthologues ATF1 and ATF2 genes could be the reason for the distinct enzyme properties, which possibly lead to the enhanced production of several flavour compounds.