Isolation of a bile salt sulfatase producing Clostridium strain from rat intestinal microflora

Abstract

Bile acid sulfates, formed in human and rat livers, are desulfated by the intestinal bacterium, termed strain S1, which desulfated the 5β-bile salt 3α-sulfates in vitro and in vivo after association with gnotobiotic rats. Strain S1 also possessed 12α-hydroxysteroid dehydrogenase and bile salt-deconjugating activities. The stain was a strict anaerobic, CO2 requiring, gram-negative, sporeforming rod and was designated as belonging to the genus Clostridium. Growth was scarce in culture media, unless in the presence of 0.1% taurine, a sulfur-containing amino acid. Addition of this substance raised the number of bacteria in thioglycolate and peptone yeast media from 104 per ml to 106 to 107 per ml and increased the colony diameter on agar medium from 0.2 mm to 0.5 to 0.9 mm. Sulfatase activity was specific for the 5β bile salt sulfates, leaving the 5α-bile salt sulfates unchanged. In addition, the sulfatase activity was cell bound, and its production was dependent on the composition of the culture medium, although no minimal sulfur medium was required for sulfatase activity.