Lactic acid bacteria in kimchi might be a cause for carcinogen production in intestine

The objective of this study was to evaluate if kimchi may be related to carcinogenesis by evaluating the activities of β-glucuronidase and β-glucosidase of lactic acid bacteria isolated from kimchi, which play a role in carcinogenesis. Thirty-six lactic acid bacteria (22 Lactobacillus spp., 11 Pediococcus pentosaceus, 2 Leuconostoc spp., and 1 Weisella cibaria) isolated from various kimchi were incubated in 10 mL of lactobacilli MRS broth at 35 °C for 20 h. Following incubation, 100 μL of each culture was suspended in 10 mL phosphate-buffered saline. The suspensions of 36 lactic acid bacteria strains were diluted with distilled water until OD500 = 1.048, and 65 μL aliquots of the suspensions were inoculated into the wells, where contained substrates to evaluate the activities of β-glucuronidase and β-glucosidase, followed by incubation at 35 °C for 4 h for the enzyme reactions. Of 36 isolates, 19 strains (52.8%) produced β-glucuronidase, 3 strains (13.9%) produced β-glucosidase, and two strains (5.6%) produced both enzymes. This result indicates that consumption of kimchi may have a potential possibility for a carcinogen production in the gut by producing the pro-carcinogenic enzymes (β-glucuronidase and β-glucosidase) of the lactic acid bacteria in kimchi.