Analysis of D-amino acid in Japanese post-fermented tea, Ishizuchi-kurocha

The d-amino acid content of Ishizuchi-kurocha, a post-fermented tea produced in Ehime, Japan, was measured. Ishizuchi-kurocha mainly contains d-glutamic and d-alanine, but it also small amount d-aspartic acid. Two types lactic bacteria, Lactiplantibacillus plantarum (L. plantarum) Levilactobacillus brevis brevis), are the main species involved fermentation during process. Therefore, acid-producing abilities strains these two isolated from were examined. Specifically, production acid, by L. observed. low. d-glutamine detected culture supernatant not bacterial cells. d-arginine cells supernatant. Both possessed at least three kinds putative racemase genes: alanine racemase, glutamate aspartate racemase. However, their expression enzyme activity remain unknown. could play an important role acids Ishizuchi-kurocha. In fact, is expected to possess effective physiological activities acids.