Aim: Tyrosol, a quorum sensing molecule in yeasts, was reported to reduce lag phase and induces hyphae formation during cell proliferation. However, evidence of any enhancing effect of tyrosol in cellular proliferation within fermentative environment is unclear. In this investigation, selected yeast cells were assessed for their ability to synthesize tyrosol followed by examining the role of the molecule during fermentation.
Methods and results: Tyrosols were characterized in four fermentative yeasts viz., Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata and Candida tropicalis isolated from traditional fermentative cakes of northeast India. All the isolates synthesized tyrosol while C. tropicalis exhibited filamentous growth in response to tyrosols retrieved from other isolates. Purified tyrosols showed protective behaviour in C. tropicalis and S. cerevisiae under ethanol mediated oxidative stress. During fermentation, tyrosol significantly enhanced growth of W. anomalus in starch medium while C. tropicalis exhibited growth enhancement in starch and glucose sources. The chief fermentative yeast S. cerevisiae showed notable enhancement in fermentative capacity in starch medium under the influence of tyrosol con-commitment of ethanol production.
Conclusion: The study concludes that tyrosol exerts unusual effect in cellular growth and fermentative ability of both Saccharomyces and non-Saccharomyces yeasts.
Significance and impact of the study: This is the first report of expression of tyrosol by non-conventional yeasts, where the molecule was found to exert enhancing effect during fermentation, thereby augmenting the process of metabolite production during traditional fermentation.
Keywords: ethanol fermentation; morphogenesis; quorum sensing; tyrosol; yeast.
© 2020 The Society for Applied Microbiology.