Yeasts are widely recognized for their industrial and fermentative relevance, but their potential as source of antibacterial compounds remains significantly underexplored compared to bacteria or filamentous fungi. This study evaluated a wide taxonomically characterized population of yeast strains for their antimicrobial activity against enteropathogenic bacteria, plant pathogens and spoilage molds, using both direct-contact and VOC-mediated assays. Our findings reveal that antimicrobial activity, including the production of inhibitory VOCs, is highly complex, depending not only on the genus and species but also on unique traits at the strain level. Metschnikowia pulcherrima exhibited a broad inhibitory spectrum against both molds and bacteria, driven by non-volatile, multifactorial mechanisms such as iron chelation and antimicrobial metabolites. In contrast, Hanseniaspora and Wickerhamomyces displayed more versatile behaviour, combining strong antifungal properties with VOC-mediated antibacterial activity. Aureobasidium and Meyerozyma genera showed a functional specialization toward antifungal activity, with limited or no effect on bacterial pathogens. The specific strains of B. bruxellensis evaluated in this study emerged as notable producers of bioactive VOCs under the tested in vitro conditions. While these results highlight a significant antagonistic potential, the observed activity appears to be strain-specific. This underscores the importance of intra-specific screening to identify 'elite' isolates with superior biocontrol traits, rather than assuming a uniform species-level metabolic profile. KEY POINTS: • Yeasts antimicrobial activity is genus/species relevant strain-specific traits. • Several yeast genera showed inhibitory activity against enteropathogenic bacteria. • B. bruxellensis represents a promising source of bioactive VOCs against both bacteria and mold.
Keywords: Anti-mold; Antibacterial; Volatile organic compounds; Yeast.
© 2026. The Author(s).