Isolation and Identification of γ-Aminobutyric acid (GABA)-producing lactic acid bacteria from Kimchi

Presumptive lactic acid bacteria (LAB) were isolated from 20 kimchi samples (total of 230 isolates) and screened for their capacity to synthesize γ-aminobutyric acid (GABA). Only 68 isolates (ca. 30%) showed this activity and were identified by a polyphasic approach consisting of morphological characteristics, catalase and biochemical tests, and species-specific polymerase chain reaction and 16S rRNA gene sequence analyses. Five species were found, including Lactobacillus plantarum (55 isolates), Lactobacillus brevis (six), Leuconostoc mesenteroides (four), Leuconostoc lactis (one), and Weissella viridescens (two). The 68 GABA-producing LAB isolates were isolated from only 11 among 20 kimchi samples indicating that they were not evenly distributed. This is the first report on the isolation of two species of Leuconostoc (Le. mesenteroides and Le. lactis) and one species of Weissella (Ws. viridescens) from kimchi with the capacity to synthesize GABA under in vitro conditions. Additionally, in previous screening results, Le. lactis and Ws. viridescens with the capacity to synthesize GABA isolated and identified from fermented food source were not observed.