Isolation and Characterization of Bifidobacterium Growth Stimulator Produced by Leuconostoc mesenteroides isolated from Kimchi

Genus Bifidobacterium is known to be beneficial gut bacteria, and some strains of Bifidobacterium are being used as probiotics. To find lactic acid bacteria (LAB) that produce Bifidobacterium growth stimulator (BGS), which promotes the growth of Bifidobacterium, we used 733 strains isolated from kimchi for BGS screening and selected strain K748, which showed the highest BGS activity at 320 AU/mL. The strain was identified as Leuconostoc mesenteroides by 16s rDNA sequencing, and the strain was named L. mesenteroides K748. BGS activity increased from 12 hours after incubation in MRS medium, reaching maximum activity (320 AU/mL) at 15 hours and maintaining that activity. The ethyl acetate extract of L. mesenteroides K748 culture supernatant promoted the growth of Bifidobacterium longum, and HPLC using this extract revealed a peak with the same retention time (7.5 minutes) as 1,4-dihydroxy-2-naphthoic acid (DHNA). LC-MS analysis revealed that the DHNA and ethyl acetate extracts of L. mesenteroides K748 had the same molecular weight, 204.1. Overall, it is possible to conclude that L. mesenteroides K748 produces DHNA that promotes the growth of Bifidobacterium.