Isolation of marine yeasts collected from the Pacific Ocean showing a high production of gamma-aminobutyric acid.

Marine yeasts were collected from coastal and deep sea areas in the Pacific Ocean and the Sea of Japan around central and northern Japan to prepare a novel type of natural seasoning. It was found that one of the marine yeasts collected from the Pacific Ocean off Hachinohe showed a high concentration of gamma-aminobutyric acid (GABA) in its extract, about 7-10 times higher than those of commercially available bread yeast and other marine yeasts. The marine yeast isolated and named Hachinohe No. 6 catalyzed the reaction from monosodium glutamate to GABA only in the presence of glucose. Subsequently, several marine yeasts belonging to the genera Pichia and Candida were found to have such catalytic activities, but not those belonging to the genus Saccharomyces. Isolate Hachinohe No. 6 was found to have the highest catalytic activity among the yeasts examined in this study.