Antimicrobial properties and death-inducing mechanisms of saccharomycin, a biocide secreted by Saccharomyces cerevisiae

Abstract

We recently found that Saccharomyces cerevisiae (strain CCMI 885) secretes antimicrobial peptides (AMPs) derived from the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) that are active against various wine-related yeast and bacteria. Here, we show that several other S. cerevisiae strains also secrete natural biocide fractions during alcoholic fermentation, although at different levels, which correlates with the antagonistic effect exerted against non-Saccharomyces yeasts. We, therefore, term this biocide saccharomycin. The native AMPs were purified by gel-filtration chromatography and its antimicrobial activity was compared to that exhibited by chemically synthesized analogues (AMP1 and AMP2/3). Results show that the antimicrobial activity of the native AMPs is significantly higher than that of the synthetic analogues (AMP1 and AMP2/3), but a conjugated action of the two synthetic peptides is observed. Moreover, while the natural AMPs are active at pH 3.5, the synthetic peptides are not, since they are anionic and cannot dissolve at this acidic pH. These findings suggest that the molecular structure of the native biocide probably involves the formation of aggregates of several peptides that render them soluble under acidic conditions. The death mechanisms induced by the AMPs were also evaluated by means of epifluorescence microscopy-based methods. Sensitive yeast cells treated with the synthetic AMPs show cell membrane disruption, apoptotic molecular markers, and internalization of the AMPs. In conclusion, our work shows that saccharomycin is a natural biocide secreted by S. cerevisiae whose activity depends on the conjugated action of GAPDH-derived peptides. This study also reveals that S. cerevisiae secretes GAPDH-derived peptides as a strategy to combat other microbial species during alcoholic fermentations.

The Assays of Bacteria-Yeast Consortia as Probiotics Candidates and Their Influences on Nutrients Utilization of Quails Diet

“…The other mechanism i.e., the cross inhibition between LAB and yeast, might be occurred. LAB produced lactic acid potentially inhibit yeast growth (Narendranath et al, 2001) or saccharomycin secreted by S. cerevisiae can inhibit bacteria (Branco et al 2017). In contrast, mutual interaction between LAB and yeast could be found at sourdough (Sieuwerts et al, 2018) or Kefir (Stadie et al, 2013).…”

The Sensory Quality Improvement of Citrus Wine through Co-Fermentations with Selected Non-Saccharomyces Yeast Strains and Saccharomyces cerevisiae

“…As presented in Table 1, co-fermentations of non-Saccharomyces yeast strains and S. cerevisiae contained lower concentrations of ethanol (9.74%-10.24%) and total acidity (7.68-8.63 g/L) than pure S. cerevisiae fermentation did (11.29% and 9.44 g/L). The Sc-Hu co-fermentation possessed a lower concentration of residual sugar (1.38 g/L), while others contained a higher level of residual sugar (2.03-2.81 g/L) than pure S. cerevisiae fermentation did (2.03 g/L), which might be caused by different sugar consumption abilities of these yeast strains [30,31]. The pH value of co-fermentations (3.37-3.47) increased compared with that of pure S. cerevisiae fermentation (3.35), which was also found in co-fermented bilberry wine [32].…”

A Control Alternative for the Hidden Enemy in the Wine Cellar

“…Posteriorly, the authors studied the antifungal action mechanism of the characterized peptides, demonstrating that they produce disruption in the cell wall integrity in H. guilliermondii [50]. Finally, when synthetic isoforms of this AMP were produced, it was observed that they are not as effective as natural peptides [51]. By assessing the biochemical characteristics of AMPs and their antifungal action mechanisms, it can be said that the use of antimicrobial peptides for biocontrol of spoilage yeasts in the winemaking industry could be an effective tool.…”

“…The antifungal capacity was quantified by measuring the diameter of the inhibition halo generated around C. intermedia LAMAP1790 (represented with red dotted lines). Left to right columns: S. cerevisiae BY4741, S. cerevisiae EC1118, B. bruxellensis LAMAP1359, B. bruxellensis LAMAP2480, B. bruxellensis LAMAP3276, and B. bruxellensis LAMAP3294[51].…”