Biotransformation of Flavonoids by Newly Isolated and Characterized NGI01 Strain from Kimchi.

Lactic acid bacteria (LAB) are generally recognized as safe (GRAS) microorganisms. This study aimed to identify novel LAB strains that can transform flavonoids into aglycones to improve bioavailability. We isolated 34 LAB strains from kimchi. The biotransformation activity of these 34 LAB strains was investigated based on α-L-rhamnosidase and β-D-glucosidase activities. Among them, 10 LAB strains with high activities were identified by 16S rRNA sequencing analysis. All tested LAB strains converted hesperidin to hesperetin (12.5-30.3%). Of these, only the NGI01 strain produced quercetin from rutin (3.9%). The optimal biotransformation conditions for the NGI01 producing hesperetin and quercetin were investigated. The highest final product concentrations of hesperetin and quercetin were 207 and 78 μM, respectively. Thus, the NGI01 strain can be a biocatalyst for producing flavonoid aglycones in the chemical and food industries.