Arginine metabolism and the role of arginine deiminase-producing microorganisms in kimchi fermentation

In this study, we evaluated the correlation between the arginine deiminase (ADI) pathway and nitrogen cycle during cabbage kimchi fermentation. Nitrite used as a food additive can be converted to carcinogenic N-nitroso compounds via reactions with secondary amines under specific conditions; thus, high nitrate- and nitrite-containing foods present a potential risk to human health. We monitored the bacterial community, levels of ADI metabolites, and nitrogen compounds present in kimchi that contained bacteria that showed low ADI activity during fermentation. The dominant growth of microorganisms with weak ADI activity reduced arginine degradation and ornithine production. Furthermore, nitrite production in kimchi samples was affected by ADI activity. The ornithine and nitrite contents in the control kimchi were 1.7- and 2.6-fold higher at week 2 than at week 1. These results suggest that ADI-associated metabolism is correlated with the nitrogen cycle in kimchi and that the addition of bacteria with weak ADI activity may reduce nitrite production in kimchi.