Heat resistance acquirement of the spoilage yeast Saccharomyces diastaticus during heat exposure.

The main fungal cause of spoilage of carbonated fermented beverages in the brewing industry is the amylolytic budding yeast Saccharomyces cerevisiae subsp. diastaticus (Saccharomyces diastaticus). Heat treatment is used to avoid microbial spoilage of the fermented beverages. Therefore, the spoilage capacity of S. diastaticus may be linked to its relative high heat resistance. Here, we assessed whether S. diastaticus can acquire heat resistance when exposed to heat stress. To this end, ascospores of S. diastaticus strain MB523 were treated at 60°C for 10 min followed by growing the surviving spores on a glucose-containing medium. The resulting vegetative cells were then allowed to sporulate again in sporulation medium. This cycle of heat treatment, vegetative growth, and sporulation was performed eight times in three independent lineages. After these eight cycles, the sporulation rate was similar to the start (∼75%) but the resulting ascospores were more heat resistant. The time needed to kill 90% of the population at 60°C (i.e. the D

Informations de copyright

Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.

Déclaration de conflit d'intérêts

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.