Aldehyde dehydrogenase activity in Lactococcus chungangensis: Application in cream cheese to reduce aldehyde in alcohol metabolism

Previous studies have shown that the metabolic capability of colonic microflora may be at least as high as that of the liver or higher than that of the whole human body. Aldehyde dehydrogenase (ALDH) is an enzyme produced by these bacteria that can metabolize acetaldehyde, produce from ethanol to acetate. Lactococcus species, which is commonly used as a starter in dairy products, was recently found to possess the ALDH gene, and the activity of this enzyme was determined. In this study, the ALDH activity of Lactococcus chungangensis CAU 28T and 11 other type strains in the genus Lactococcus was studied. Only 5 species, 3 of dairy origin (Lactococcus lactis ssp. lactis KCTC 3769T, Lactococcus lactis ssp. cremoris KCCM 40699T, and Lactococcus raffinolactis DSM 20443T) and 2 of nondairy origin (Lactococcus fujiensis NJ317T and L. chungangensis CAU 28T), showed ALDH activity and possessed a gene encoding ALDH. All of these strains were capable of making cream cheese. Among the strains, L. chungangensis produced cream cheese that contained the highest level of ALDH and was found to reduce the level of acetaldehyde in the serum of mice. These results predict a promising role for L. chungangensis CAU28T to be used in cheese that can be developed as functional food.