Algal amphidinols, an alternative to sulfites in the fight against Brettanomyces bruxellensis

This study evaluated the biocidal activity of a microalgal extract from Amphidinium carterae under oenological conditions to limit Brettanomyces bruxellensis development in red wines over 150 days. Viable and culturable cell concentrations were analyzed during this period. To evaluate the treatment effect on volatile phenols production by B. bruxellensis , 4-ethylphenol and 4-ethylguaiacol concentrations were measured. The involvement of amphidinols (AMs) in the biocidal activity of the extract was also demonstrated under oenological conditions. Finally, the degradation of amphidinol18 in the wine matrix was monitored by HPLC in order to determine the persistence of the biocidal molecule in wine. Our results indicate that the microalgal extract completely inhibits both the growth of B. bruxellensis and the production of volatile phenols under oenological conditions, regardless of the strain analyzed. It was demonstrated that the efficiency of the treatment depends on the initial concentration of cell in the wine. The involvement of AMs in the biocidal activity of the algal extract was confirmed. Finally, it was shown that amphidinol18 gradually degrades and becomes undetectable after 30 days in the wine matrix. The results demonstrate the potential of AMs as a promising alternative to sulfites as an anti- Brettanomyces agent in oenology. • Amphidinols inhibit B.bruxellensis and consequently volatile phenols synthesis in wine • Treatment works regardless of the strain, although it depends on cell concentration • Amphidinols are confirmed as the biocidal compounds of the algal extract • After 30 days, amphidinols degrade in the red wine matrix • First proof of fungicide activity of amphidinols in red wine