Absence of Cholic Acid 7α-Dehydroxylase Activity in the Strains ofLactobacillusandBifidobacteriumFreshly Isolated from Human Feces

• Published in: Journal of Intestinal Microbiology Vol. 11; no. 2; pp. 105 - 108
• Main Authors: SATO, Mikiko, SAKAITANI, Yukiko, TAKAHASHI, Takuya, MOROTOMI, Masami
• Format: Journal Article
• Language: Japanese
• Published: The Intestinal Microbiology Society 1998
• Subjects: 7α-dehydroxylase; Bifidobacterium; bile acid metabolism; Lactobacillus
• ISSN: 1343-0882; 1349-8363
• DOI: 10.11209/jim1997.11.105

We have previously reported the absence of cholic acid 7α-dehydroxylase activity in several industrial stock cultures as well as intestinal strains of lactic acid bacteria. In this study, the presence of 7α-dehydroxylase activity in the bile acids of human intestinalBifidobacteriumandLactobacillusstrains was investigated. Twelve strains ofBifidobacteriumsp. and 10 strains of Lactobacillus sp. were freshly isolated from six healthy human subjects and tested for their ability to produce deoxycholic acid from cholic acid. The production of deoxycholic acid was quantitatively measured by HPLC analysis. In growing cultures, more than 90% of the 150μg/ml of cholic acid was transformed to deoxycholic acid by a positive control strain, Eubacterium lentum-like strain c-25, after 7 days of anaerobic incubation. However, none of the test strains showed the production of deoxycholic acid as growing cultures. These results indicate, together with the results of our previous study, that strains ofBifidobacteriumandLactobacillusregardless of their origin or subculture, lack bile acid 7α-dehydroxylase.