Abstract

Nuruk is a fermenting starter that is involved in the pro-duction of alcoholic beverages, and has been used in South Korea for a very long time. To analyze the fungal diversity, we collected a total of 59 nuruk samples from several com-panies and persons in 2013 to 2014, and obtained 364 iso-lates. All of the single isolated fungi were identified, both morphologically and molecularly, based on the sequences of ribosomal RNA gene [18S, ITS1-5.8S-ITS2, and 26S (D1/D2 region)]. In 46 nuruk samples out of 59 (78%), Saccharo-mycopsis fibuligera, a dimorphic yeast, was most frequently isolated. Among the filamentous fungi, Aspergillus and Lich-theimia were found in more than 50% of the samples with lower colony forming unit (CFU/g of sample) than those of yeasts. The yeasts S. fibuligera and Wickerhamomyces ano-malus were counted with maximum 1.3 – 1.8 × 108 CFU/g. Among Mucorales fungi, Lichtheimia and Mucor were iso-lated in much higher numbers than Rhizopus and Rhizo-mucor. Overall, the home-made nuruks tend to contain more diverse filamentous fungi than the commercial nuruks. To acquire industrially useful filamentous fungi and yeasts, we analyzed the enzyme activities of α-amylase, glucoamylase and acid protease associated with brewing properties for 131 strains. Aspergillus oryzae and S. fibuligera had high α- and glucoamylase activities and most isolates of Lichtheimia ramosa had high acid protease activity. For further applica-tions, 27 fungal strains were chosen based on isolation fre-quencies from nuruk, and the ability to produce useful en-zyme.

• Keywords: fungal diversity; nuruk; Saccharomycopsis fibu-ligera; enzyme activity; application