Physicochemical and functional characteristics of non-Saccharomyces cerevisiae isolated from traditional nuruk

This study was conducted to evaluate the alcohol-producing abilities and functional characteristics of five strains of non-Saccharomyces cerevisiae (NSC), namely, Kluyveromyces marxianus KJ-L, Wickerhamomyces anomalus KJ-1, W. anomalus CP-2, Pichia anomalus HAN-1, and Meyerozyma guilliermondii SU-L, which were isolated from Korean traditional nuruk. The selected yeast strains produced large amounts of alcohol using a carbon source of 20% glucose and were identified as NSC based on their 18S rDNA sequences. The optimal growth temperature and pH of the NSC except for M. guilliermondii SU-L were 25°C and 4.0, respectively. Two NSC strains, KJ-L and CP-2, produced 5–10% more alcohol compared to that produced by S. cerevisiae LP (SC LP) control. Although the α-amylase and ß-glucosidase activities were slightly lower in the NSC strains than in the SC LP, glucoamylase activity was 1.4-fold higher in the NSC strains than in the SC LP. The α-glucosidase inhibition activity evaluated using 1% acarbose was 29-fold higher for K. marxianus KJ-L and P. anomalus HAN-1 than that of SC LP. The five strains of NSC exhibited higher angiotensin-converting enzyme inhibitory activity with inhibition rates of 51.7–61.7% compared to that of SC LP (37.3%). The tyrosinase inhibition activities of NSC (86.4-91.5%) and SC LP (94.9%) were significantly higher than that of the positive control, kojic acid. These NSC yeast show high potential for industrial application as domestic starters for manufacturing fermented foods and cosmetics based on their physiological activities and functional characteristics.