Zygosaccharomyces kombuchaensis: Thephysiology of a new species related to the spoilage yeasts Zygosaccharomyces lentus and Zygosaccharomyces bailii
Hazel Steels, Steve A. James, Chris J. Bond, Ian N. Roberts, Malcolm Stratford
Zygosaccharomyces kombuchaensis was recently discovered in the 'tea fungus' used to make fermented tea. Z. kombuchaensis was shown by ribosomal DNA sequencing to be a novel species, and a close relative of Zygosaccharomyces lentus, from which it could not be distinguished by conventional physiological tests. Z. lentus was originally established as a new taxon by growth at 4?C, sensitivity for heat and oxidative stress, and lack of growth in aerobic shaken culture at temperatures above 25C. Subsequent analysis of Z. kombuchaensis reveals that this species shares these unusual characteristics, confirming its close genealogical relationship to Z. lentus. Detailed physiological data from a number of Z. kombuchaensis and Z. lentus strains clearly demonstrate that these two species can, in fact, be distinguished from one another based on their differing resistance/sensitivity to the food preservatives benzoic acid and sorbic acid. The spoilage yeasts Zygosaccharomyces bailii and Z. lentus are resistant to both acetic acid and sorbic acid, whereas Z. kombuchaensis is resistant to acetic acid but sensitive to sorbic acid. This would indicate that Z. kombuchaensis strains lack the mechanism for resistance to sorbic acid, but possess the means of resistance to acetic acid. This observation would, therefore, suggest that these two resistance mechanisms are different and that in all probability, acetic and sorbic acids inhibit yeast growth by different modes of action. Z. kombuchaensis strains were also sensitive to benzoic acid, again suggesting inhibition dissimilar from that to acetic acid.
Citation: FEMS yeast research, 2(2), 113-121.
Study Mailing Address:
Food Processing Group, Unilever RpD, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK b National Collection of Yeast Cultures, Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK
Date Updated: January 20, 2021