Inhibition of spoilage yeasts in cheese by killer yeast Williopsis saturnus var. saturnus

In the food industry, food spoilage is a real issue that can lead to a significant amount of waste. Although current preservation techniques are being applied to reduce the occurrence of spoilage microorganisms, the problem persists. Food spoilage yeast are part of this dilemma, with common spoilers such as Zygosaccharomyces, Kluyveromyces, Debaryomyces and Saccharomyces frequently encountered. Antimicrobial peptides derived from plants have risen in popularity due to their ability to reduce spoilage. This study examines the potential application of a synthetic defensin peptide derived from barley endosperm. Its inhibitory effect against common spoilage yeasts, its mechanisms of action (membrane permeabilisation and overproduction of reactive oxygen species), and its stability in different conditions were characterised. The safety of the peptide was evaluated through a haemolysis and cytotoxicity assay, and no adverse effects were found. Both assays were performed to understand the effect of the peptide if it were to be consumed. Its ability to be degraded by a digestive enzyme was also examined for its safety. Finally, the peptide was successfully applied to different beverages and maintained the same inhibitory effects in apple juice as was observed in the antiyeast assays, providing further support for its application in food preservation.

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Non-Saccharomyces as Biotools to Control the Production of Off-Flavors in Wines

Molecules ◽

10.3390/molecules26154571 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4571

Author(s):

Antonio Morata ◽

Iris Loira ◽

Carmen González ◽

Carlos Escott

Keyword(s):

Global Warming ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Wine Quality ◽

Microbial Spoilage ◽

Spoilage Yeasts ◽

Off Flavors ◽

Chemical Preservatives ◽

Saccharomyces Yeasts ◽

Lachancea Thermotolerans

Off-flavors produced by undesirable microbial spoilage are a major concern in wineries, as they affect wine quality. This situation is worse in warm areas affected by global warming because of the resulting higher pHs in wines. Natural biotechnologies can aid in effectively controlling these processes, while reducing the use of chemical preservatives such as SO2. Bioacidification reduces the development of spoilage yeasts and bacteria, but also increases the amount of molecular SO2, which allows for lower total levels. The use of non-Saccharomyces yeasts, such as Lachancea thermotolerans, results in effective acidification through the production of lactic acid from sugars. Furthermore, high lactic acid contents (>4 g/L) inhibit lactic acid bacteria and have some effect on Brettanomyces. Additionally, the use of yeasts with hydroxycinnamate decarboxylase (HCDC) activity can be useful to promote the fermentative formation of stable vinylphenolic pyranoanthocyanins, reducing the amount of ethylphenol precursors. This biotechnology increases the amount of stable pigments and simultaneously prevents the formation of high contents of ethylphenols, even when the wine is contaminated by Brettanomyces.

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Killer yeasts as biocontrol agents of spoilage yeasts and bacteria isolated from wine

BIO Web of Conferences ◽

10.1051/bioconf/20140302001 ◽

2014 ◽

Vol 3 ◽

pp. 02001

Author(s):

Miguel Fernández de Ullivarri ◽

Lucía M. Mendoza ◽

Raúl R. Raya

Keyword(s):

Biocontrol Agents ◽

Killer Yeasts ◽

Spoilage Yeasts

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Sphingolipid biosynthesis upregulation by TOR complex 2–Ypk1 signaling during yeast adaptive response to acetic acid stress

Biochemical Journal ◽

10.1042/bcj20160565 ◽

2016 ◽

Vol 473 (23) ◽

pp. 4311-4325 ◽

Cited By ~ 27

Author(s):

Joana F. Guerreiro ◽

Alexander Muir ◽

Subramaniam Ramachandran ◽

Jeremy Thorner ◽

Isabel Sá-Correia

Keyword(s):

Acetic Acid ◽

Protein Kinase ◽

Cellular Response ◽

Molecular Mechanisms ◽

Acid Stress ◽

Acid Tolerance ◽

Industrial Biotechnology ◽

Acetic Acid Tolerance ◽

Spoilage Yeasts ◽

Sphingolipid Biosynthesis

Acetic acid-induced inhibition of yeast growth and metabolism limits the productivity of industrial fermentation processes, especially when lignocellulosic hydrolysates are used as feedstock in industrial biotechnology. Tolerance to acetic acid of food spoilage yeasts is also a problem in the preservation of acidic foods and beverages. Thus understanding the molecular mechanisms underlying adaptation and tolerance to acetic acid stress is increasingly important in industrial biotechnology and the food industry. Prior genetic screens for Saccharomyces cerevisiae mutants with increased sensitivity to acetic acid identified loss-of-function mutations in the YPK1 gene, which encodes a protein kinase activated by the target of rapamycin (TOR) complex 2 (TORC2). We show in the present study by several independent criteria that TORC2–Ypk1 signaling is stimulated in response to acetic acid stress. Moreover, we demonstrate that TORC2-mediated Ypk1 phosphorylation and activation is necessary for acetic acid tolerance, and occurs independently of Hrk1, a protein kinase previously implicated in the cellular response to acetic acid. In addition, we show that TORC2–Ypk1-mediated activation of l-serine:palmitoyl-CoA acyltransferase, the enzyme complex that catalyzes the first committed step of sphingolipid biosynthesis, is required for acetic acid tolerance. Furthermore, analysis of the sphingolipid pathway using inhibitors and mutants indicates that it is production of certain complex sphingolipids that contributes to conferring acetic acid tolerance. Consistent with that conclusion, promoting sphingolipid synthesis by adding exogenous long-chain base precursor phytosphingosine to the growth medium enhanced acetic acid tolerance. Thus appropriate modulation of the TORC2–Ypk1–sphingolipid axis in industrial yeast strains may have utility in improving fermentations of acetic acid-containing feedstocks.

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Isolation of a wild Candida killer yeast with a novel killer property.

Agricultural and Biological Chemistry ◽

10.1271/bbb1961.52.2791 ◽

1988 ◽

Vol 52 (11) ◽

pp. 2791-2796

Author(s):

Yoichi YOKOMORI ◽

Hiroichi AKIYAMA ◽

Kenichi SHIMIZU

Keyword(s):

Killer Yeast

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Assessing Genetic Diversity among Brettanomyces Yeasts by DNA Fingerprinting and Whole-Genome Sequencing

Applied and Environmental Microbiology ◽

10.1128/aem.00601-14 ◽

2014 ◽

Vol 80 (14) ◽

pp. 4398-4413 ◽

Cited By ~ 45

Author(s):

Sam Crauwels ◽

Bo Zhu ◽

Jan Steensels ◽

Pieter Busschaert ◽

Gorik De Samblanx ◽

...

Keyword(s):

Genetic Diversity ◽

Dna Fingerprinting ◽

Wine Industry ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Content Type ◽

Carbon And Nitrogen ◽

Spoilage Yeasts ◽

Off Flavors ◽

Carbon And Nitrogen Metabolism

ABSTRACTBrettanomycesyeasts, with the speciesBrettanomyces(Dekkera)bruxellensisbeing the most important one, are generally reported to be spoilage yeasts in the beer and wine industry due to the production of phenolic off flavors. However,B. bruxellensisis also known to be a beneficial contributor in certain fermentation processes, such as the production of certain specialty beers. Nevertheless, despite its economic importance,Brettanomycesyeasts remain poorly understood at the genetic and genomic levels. In this study, the genetic relationship between more than 50Brettanomycesstrains from all presently known species and from several sources was studied using a combination of DNA fingerprinting techniques. This revealed an intriguing correlation between theB. bruxellensisfingerprints and the respective isolation source. To further explore this relationship, we sequenced a (beneficial) beer isolate ofB. bruxellensis(VIB X9085; ST05.12/22) and compared its genome sequence with the genome sequences of two wine spoilage strains (AWRI 1499 and CBS 2499). ST05.12/22 was found to be substantially different from both wine strains, especially at the level of single nucleotide polymorphisms (SNPs). In addition, there were major differences in the genome structures between the strains investigated, including the presence of large duplications and deletions. Gene content analysis revealed the presence of 20 genes which were present in both wine strains but absent in the beer strain, including many genes involved in carbon and nitrogen metabolism, and vice versa, no genes that were missing in both AWRI 1499 and CBS 2499 were found in ST05.12/22. Together, this study provides tools to discriminateBrettanomycesstrains and provides a first glimpse at the genetic diversity and genome plasticity ofB. bruxellensis.

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