Investigation of beer-spoilage ability ofDekkera/Brettanomycesyeasts and development of multiplex PCR method for beer-spoilage yeasts

Abstract

There have been many beer-spoilage incidents caused by wild yeasts. Saccharomyces cerevisiae, Dekkera anomala and D. bruxellensis have been recognized as beer-spoilage yeasts in the brewing industry. In contrast, the beer spoilage ability of Brettanomyces custersianus has not been well characterized, although this species was isolated from beer. In this study, the beer-spoilage ability of currently described Dekkera/Brettanomyces yeast species was investigated. As a consequence, D. anomala, D. bruxellensis and B. custersianus were shown to grow in commercial beers. On the other hand, the remaining two Brettanomyces species, B. naardenensis and B. nanus, did not grow in beer. These results indicate that B. custersianus should be recognized as a beer-spoilage species, in addition to S. cerevisiae, D. anomala, and D. bruxellensis. Therefore we developed multiplex polymerase chain reaction (PCR) for the simultaneous detection and identification of B. custersianus and the other beer-spoilage yeast species. For this purpose, PCR primers were designed in the internal transcribed spacer region or 26S rDNA, and each PCR product was made in different sizes to easily discriminate the species from electrophoretic results. Specificity, reactivity and sensitivity of the designed primers were evaluated. As a result, the developed multiplex PCR method was shown to have high specificity and reactivity, and therefore was considered as an effective tool to identify beer-spoilage yeast species. This tool can contribute to microbiological quality assurance in breweries.

Assembly and Analysis of the Genome Sequence of the Yeast Brettanomyces naardenensis CBS 7540

“…All above-mentioned B. naardenensis strains were described as soft drink spoilage microorganisms, suggesting notable species tolerance to low pH and osmotic stress. The low number of reports on the occurrence of B. naardenensis in wine [9] and beer [6] indicates that the species is less competitive in these environments than B. bruxellensis, B. anomala, and B. custersianus [57]. A genome hybridization event resulting in highly heterozygous allotriploid genotype of some Australian B. bruxellensis wine strains could confer a selective advantage of this species in the presence of the high levels of sulfur dioxide, a preservative used in winemaking [22,23,58].…”

Beer Safety: New Challenges and Future Trends within Craft and Large-Scale Production

“…Non-alcoholic and low-alcoholic flavoured beers are microbiologically unstable due to their high sugar content, which can increase the number of spoiled wild yeast species [ 45 ]. Saccharomyces, Pichia, Rhodotorula, Alternaria, Hansenia, Wickerhamomyces, and Cladosporium were identified in non-alcoholic beer before pasteurisation [ 46 ]. To investigate beer spoiling capabilities, Dekkera/Brettanomyces yeast was inoculated into two commercial bottled beers (Japanese pilsner-type and malt beer) at a concentration of 10 3 cells/mL (10 5 cells/bottle).…”

Metabolomics of Non-Saccharomyces Yeasts in Fermented Beverages

“…Brettanomyces yeasts, also known as Dekkera, are the most common non-Saccharomyces yeasts used by the brewing and wine-making industries. Brettanomyces are traditionally considered to be wine spoilage yeasts [29,30], particularly due to their production of 4-ethylguaiacol (4-EG) and 4-ethylphenol (4-EP), with flavours described as medicinal, barnyard, horsy, earthy, spicy, and clove-like [29].…”