Repurposing brewery contaminant yeast as production strains for low‐alcohol beer fermentation

Abstract

A number of fungal isolates were recently obtained from a survey of the microbiota of multiple breweries and brewery products. Here, we sought to explore whether any of these brewery contaminants could be repurposed for beneficial use in beer fermentations, with particular focus on low-alcohol beer. There were 56 yeast strains first screened for the utilization of different carbon sources, ability to ferment brewer's wort, and formation of desirable aroma compounds. A number of strains appeared maltose-negative and produced desirable aromas without obvious off-flavours. These were selected for further scaled-up wort fermentations. The selected strains efficiently reduced wort aldehydes during fermentation, thus eliminating undesirable wort-like off-flavours, and produced a diverse volatile aroma profile. Two strains, Trigonopsis cantarellii and Candida sojae, together with a commercial Saccharomycodes ludwigii reference strain, were selected for 30-L-scale wort fermentations based on aroma profile and similarity to a commercial reference beer during sensory analysis using projective mapping. Both strains performed comparably to the commercial reference, and the T. cantarellii strain in particular, produced low amounts of off-flavours and a significantly higher amount of the desirable monoterpene alcohol trans-geraniol. The strain was also sensitive to common food preservatives and antifungal compounds and unable to grow at 37 C, suggesting it is relatively easily controllable in the brewery, and appears to have low risk of pathogenicity. This study shows how the natural brewery microbiota can be exploited as a source of non-conventional yeasts for low-alcohol beer production.

Maltose-Negative Yeast in Non-Alcoholic and Low-Alcoholic Beer Production

“…Sourdough cultures (Kazachstania servazzii and Pichia fermentans) [6] have also investigated. Other environments that could be investigated for possible maltose-negative yeast that might be useful in brewing include: Trigonopsis cantarellii and Candida sojae [92], honey (Zygosaccharomyces rouxii) [89], fermented honey by-products (Hanseniaspora uvarum, Wickerhamomyces anomalus, Zygosaccharomyces rouxii, and Zygosaccharomyces bailii) [93], various exotic plants [7], and cold habitats such as Antarctica (psychrophilic yeast strains-Mrakia gelida) [36,94].…”

“…* All S. ludwigi data were compatible among the references. For an easier evaluation, all S. ludwigi data about sugar consumption, POF production, and flocculation were combined: Maltose utilisation data was obtained from [92]; VTT-C181010 [89]; DBVPG 3010, 3304, 3398, 3931, 4116, and 6771 [10]; TUM SL 17; WSL17 [36]; Glucose utilisation data was obtained from [89]; DBVPG 3010, 3304, 3398, 3931, 4116, and 6771 [10]; TUM SL 17 [36], WSL17; Fructose utilisation data was obtained from [10]; TUM SL 17; WSL17 [36]; Sucrose utilisation data was obtained from [89]; DBVPG 3010, 3304, 3398, 3931, 4116, and 6771 [10], TUM SL 17; WSL17 [36]; POF info was obtained from [10]; TUM SL 17: flocculation% info was obtained from 27.1 [6]-60 ± 7 [10]; TUM SL 17. ** According to Kurtzman, et al [104], growth on maltose "variable" [5].…”

Fungal diversity on brewery filling hall surfaces and quality control samples

“…Trigonopsis cantarellii was not (Krogerus et al, 2021). S. cerevisiae isolates from beer bottling lines lacked biofilm forming ability and were thought to colonize more mature biofilms (Timke et al, 2007).…”

Metabolomics of Non-Saccharomyces Yeasts in Fermented Beverages

“…Most methods to produce alcohol-free beer, such as distillation to remove ethanol after fermentation, are costly and impact the organoleptic properties of the beverage resulting in beers with little depth of flavour, aroma, or character [66][67][68][69]. Biological methods of reducing the ethanol content are therefore promising alternatives.…”