Diversity of lactic acid bacteria (LAB) in Makgeolli and their production of γ-aminobutyric acid

Abstract

Makgeolli is made from rice or flour, yeast, and nuruk, a fermentation starter. The flavor of makgeolli is affected by sugars, amino acids, organic acids and volatile flavor compounds produced by various microorganisms. In this study, lactic acid bacteria (LAB) were isolated from unsterilized makgeolli samples collected from several provinces in Korea, and then later identified. Under anaerobic conditions, LAB density ranged from 5.0×106 to 1.5×108 CFU/mL; yeast density ranged from 2.5×107 to 1.5×108 CFU/mL. Of the LAB isolated from makgeolli, 1,126 were analyzed using restriction fragment length polymorphism (PCR-RFLP) analysis of 16S rRNA, which allowed for classification into five groups. Of the 1,126 LABs tested, 130 produced γ-aminobutyric acid (GABA).