Saccharomycin, a biocide from S. cerevisiae that kill-off other yeasts

ABSTRACT: Introduction: Saccharomyces cerevisiae plays an important role in alcoholic fermentation and is involved in the production of wine, beer and bread. Recent studies [1–7] showed that S. cerevisiae secretes antimicrobial peptides (AMPs), named “saccharomycin”, derived from the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) that are active against a variety of wine-related microbial species. AMPs are low molecular weight proteins with broad antimicrobial spectrum of action against bacteria, viruses, and fungi [8]. Organisms use AMPs for defence against infection and membrane interaction appears to be the key to this antimicrobial function: generally they adopt amphiphilic structures that interact with the infectious agent’s membrane. AMPs constitute a promising source as alternatives to: i) combat pathogenic bacteria resistant to common antibiotics and ii) substitute chemical preservatives in food-fermented products such as wine. The aim of this study was to discover the mode of action of these peptides by detailed chemical structure characterisation and cell contact mechanism.info:eu-repo/semantics/publishedVersio

Identification of novel GAPDH-derived antimicrobial peptides secreted by Saccharomyces cerevisiae and involved in wine microbial interactions

Saccharomyces cerevisiae plays a primordial role in alcoholic fermentation and has a vastworldwide application in the production of fuel-ethanol, food and beverages. The dominance of S. cerevisiae over other microbial species during alcoholic fermentations has been traditionally ascribed to its higher ethanol tolerance. However, recent studies suggested that other phenomena, such as microbial interactions mediated by killer-like toxins, might play an important role. Here we show that S. cerevisiae secretes antimicrobial peptides (AMPs) during alcoholic fermentation that are active against a wide variety of wine-related yeasts (e.g. Dekkera bruxellensis) and bacteria (e.g. Oenococcus oeni). Mass spectrometry analyses revealed that these AMPs correspond to fragments of the S. cerevisiae glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein. The involvement of GAPDH-derived peptides in wine microbial interactions was further sustained by results obtained in mixed cultures performed with S. cerevisiae single mutants deleted in each of the GAPDH codifying genes (TDH1-3) and also with a S. cerevisiae mutant deleted in the YCA1 gene, which codifies the apoptosis-involved enzyme metacaspase. These findings are discussed in the context of wine microbial interactions, biopreservation potential and the role of GAPDH in the defence system of S. cerevisiae