Wine-lees peptide fractions suppress grapevine trunk-disease fungi in experimental tests
Hydrolysed fractions derived from wine lees reduced the growth and reproduction of two fungi associated with Petri disease and limited wood discoloration in plant assays. The published research suggests a possible circular-economy route from winery by-product to biological crop protection, but field performance, costs, application methods and regulatory requirements remain unresolved.
A by-product and a vineyard threat
A study published on August 12 in Systems Microbiology and Biomanufacturing reports that peptide-rich mixtures made from wine lees—the sediment deposited in fermentation tanks and barrels—showed antifungal activity against Phaeomoniella chlamydospora and Phaeoacremonium minimum. Both fungi are closely associated with Petri disease, a grapevine trunk disease that can infect the wood of young vines and cause discoloration, tissue death, striped leaves, impaired growth, wilting and, in severe cases, vine death.1
The work addresses both grapevine disease and the management of an abundant winery residue. According to the researchers, lees are the wine sector’s second-largest by-product and represent about 25% of its total by-products. They contain living and dead yeast cells as well as proteins, peptides, polysaccharides, lipids and polyphenols. Their composition, however, varies with grape variety, yeast strain and fermentation process, making control of the starting material a central concern.1
Interest in biological control has grown because effective chemical options have remained limited since sodium arsenite was prohibited over human-health risks. The study nevertheless does not establish the lees-derived material as a commercial vineyard treatment: its evidence comes from laboratory work and experimental plant assays rather than large trials in commercial vineyards.1
How the antifungal fractions were produced
The researchers created a multistage process beginning with controlled fermentations. These used Saccharomyces monocultures and sequential inoculations involving non-Saccharomyces strains. The resulting lees underwent ultrasound-assisted autolysis, enzymatic hydrolysis and ultrafiltration at a threshold of 3 kilodaltons, breaking yeast-derived material into smaller fractions for biological testing.1
Fermentation conditions were treated as an upstream quality-control tool. By choosing yeast strains and inoculation sequences, producers could potentially influence the chemical composition and antifungal strength of the resulting fractions. This also means that fermentation choices made during wine production may affect the potential value of the residual lees.1
Effects on fungal growth and reproduction
The untreated, high-molecular-weight autolysates did not inhibit fungal growth. Fractions obtained after hydrolysis, by contrast, reduced mycelial growth of Phaeoacremonium minimum by 45%–75% and that of Phaeomoniella chlamydospora by 40%–57%. Conidia production fell by as much as 92% for one pathogen and 61% for the other, indicating effects on fungal reproduction as well as vegetative growth.1
Experimental plant assays produced further reductions. Depending on the pathogen, tested fraction and measurement set, wood discoloration declined by 47%–52% in one set and 35%–73% in another. Endophytic fungal growth was reduced by 63%–84% and 80%–91%. The researchers interpreted the contrast between inactive autolysates and active hydrolysed fractions as evidence that hydrolysis is important, possibly because antifungal activity emerges when yeast proteins are divided into smaller peptides.1
Chemical signals and possible applications
Untargeted metabolomic analysis using UHPLC-ESI-TIMS-QTOF revealed chemical signatures dependent on yeast strain and fermentation conditions. The researchers identified 448 features that varied among fermentation conditions. A separate activity-based correlation fingerprinting method found 49 putative biomarkers negatively associated with pathogen growth; these candidates may help identify the molecules responsible for activity and inform the design of future production processes.1
If larger studies confirm the results, lees could become a raw material for agricultural inputs rather than solely a disposal burden, linking winery-waste valorisation with biological vineyard protection. The proposed approach treats lees as a material whose activity might be adjusted through fermentation design, enzymatic treatment and physical separation.1
Field validation still required
The findings remain preliminary because the fractions have not been validated in large commercial-vineyard field trials. Further work must determine their consistency, production cost, application methods, regulatory pathway and effectiveness under real growing conditions. Weather, soil, vine age and simultaneous infections may all alter disease pressure and treatment performance, so the current results support further crop-protection research rather than claims of a ready-to-use product.1
Sources
Written by the Dionysus editors from the sources above.
