Physiological and fermentative performance of non- Saccharomyces yeasts isolated from kombucha for beer production.

This article focuses on isolating, identifying, and characterizing non-Saccharomyces yeasts from kombucha for potential use in beer production, particularly low-alcohol and sour beer styles. Nineteen yeast strains were identified, including Brettanomyces bruxellensis, Pichia kluyveri, and Saccharomycodes ludwigii, with several strains demonstrating desirable physiological traits such as ethanol and hop tolerance, maltose fermentation, and flocculation capacity. Fermentation trials at 10 °C and 20 °C showed that all non-Saccharomyces yeasts produced alcohol-free beers (<0.5% ethanol) at the lower temperature, while at 20 °C, only P. kluyveri L431 maintained non-alcoholic levels; other strains produced beers with reduced or moderate alcohol content. Additionally, certain strains produced higher acetic acid concentrations, indicating potential for sour beer production. The study highlights the importance of selecting yeast strains based on beer style and fermentation conditions, noting the need for further research on volatile compounds and sensory profiles.