Long-chain fatty acid compositions and volatile metabolite patterns of yeasts associated with wine

[摘要] A) In Chapter 1 the need for a yeast identification system in the wineindustry is highlighted. The definition, as well as taxonomicdevelopment of the ascomycetous yeasts are discussed as well as theproblems encountered.B) In Chapter 2 the cellular long-chain fatty acid compositions of 103yeast strains representing 38 species related to the wine industrywere determined gaschromatographically. It was possible todifferentiate between most species examined as well as between somestrains within species. A correlation was observed between long-chainfatty acid composition and complexity of cell differentiation, geneticrecombination, carbon source- and ethylamine utilization andresistance to cycloheximide. A phylogenetic scheme for the genusKluyveromyces was constructed on the basis of the abovementionedfeatures.C) Chapter 3 includes the use of volatile metabolites in theidentification of winery-associated yeasts. According to the resultsit was possible to differentiate between the Saceh. cerevisiae and S.pombe strains.D) A Discussion and Conclusions is presented in Chapter 4. This includesa discussion on the identification of wine yeasts and the relationbetween long-chain fatty acid composition, pseudomycelium formation,genetic recombination, carbon source- and ethylamine utilization andresistance to cycloheximide. A possible relation between thesimilarity in long-chain fatty acid compositions and DNA homologybetween yeasts strains is indicated. The use of volatile metabolites in the identification of wine yeasts is also discussed.

[发布机构] University of the Free State