Isolation of wild yeasts from Olympic National Park and Moniliella megachiliensis ONP131 physiological characterization for beer fermentation.

Thousands of yeasts have the potential for industrial application, though many were initially considered contaminants in the beer industry. However, these organisms are currently considered important components in beers because they contribute new flavors. Non- Saccharomyces wild yeasts can be important tools in the development of new products, and the objective of this work was to obtain and characterize novel yeast isolates for their ability to produce beer. Wild yeasts were isolated from environmental samples from Olympic National Park and analyzed for their ability to ferment malt extract medium and beer wort. Six different strains were isolated, of which Moniliella megachiliensis ONP131 displayed the highest levels of attenuation during fermentations. We found that M. megachiliensis could be propagated in common yeast media, tolerated incubation temperatures of 37 °C and a pH of 2.5, and was able to grow in media containing maltose as the sole carbon source. Yeast cultivation was considerably impacted (p < 0.05) by lactic acid, ethanol, and high concentrations of maltose, but ONP131 was tolerant to high salinity and hop acid concentrations. This is one of the first physiological characterizations of M. megachiliensis , which has potential for the production of beer and other fermented beverages. • Yeast strains were isolated from environmental samples from Olympic National Park. • Moniliella megachiliensis was the most promising yeast after fermentation tests. • M. megachiliensis tolerates 37 °C, ethanol up to 6%, 5% NaCl, and metabolizes maltose. • High concentrations of α-acids from hops had no impact on M. megachiliensis growth. • M. megachiliensis is a novel yeast for beer production. [ABSTRACT FROM AUTHOR]