Yeast-derived biomolecule mixtures from wine lees display antimicrobial activity: an integrated bioprocess approach against grapevine pathogens

Abstract

Grapevine trunk diseases threaten sustainable viticulture, while wine lees remain an underexploited biocontrol-relevant by-product within the circular economy framework. An integrated bioprocess was developed to upgrade lees into high-molecular-weight biomolecule mixtures and low-molecular-weight peptide-enriched fractions through a defined sequence of unit operations: fermentation design by using Saccharomyces monocultures and sequential inoculations with non- Saccharomyces strains, ultrasound-assisted autolysis, enzymatic hydrolysis, and 3 kDa ultrafiltration. The antifungal activity of the products was tested in vitro and in vivo against Phaeomoniella chlamydospora and Phaeoacremonium minimum , the two main pathogens that cause Petri disease in grapevine. The results demonstrated that high-molecular-weight autolysates showed no inhibition. The post-hydrolysis fractions reduced mycelial growth of Phaeoacremonium minimum by 45%–75% and Phaeomoniella chlamydospora by 40%–57%, and decreased conidiation by up to 92% and 61%, respectively. They also reduced symptoms (wood discoloration) by 47%–52% and 35%–73% and endophytic fungal growth by 63%–84% and 80%–91% respectively. Those results indicate an association between hydrolysis and the appearance of antifungal activity. Untargeted metabolomics employing liquid chromatography–mass spectrometry (UHPLC–ESI–TIMS–QTOF) highlighted strain- and fermentation-dependent secondary metabolite signatures, with 448 features differentiating across fermentation conditions. Activity-based correlation fingerprinting identified 49 putative biomarkers negatively associated with pathogen growth. Overall, fermentation design functions as a controllable upstream quality parameter, offering a scalable circular economy pathway for the production of antifungal bioproducts derived from winery waste.

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