[Study on ursodeoxycholic acid biotransformation by three strains of clostridia]

Using the improved TLC procedure, we measured the conversion rates of ursodeoxycholic acid(UDCA) from chenodeoxycholic acid (CDCA) by 3 strains of clostridia--C. perfringens HS-10, C. butyricum DL-20 and LQ-29 isolated. The orthogonal test was used to determine the optical conditions of biotransformation for HS-10. It was found that the conversion rate of UDCA by HS-10 was over 80% during 6-48 h in RCM medium containing 0.2 mmol/L CDCA. The UDCA conversion rates were still over 70% when the CDCA concentrations were as high as 0.8-1.0 mmol/L. In addition, the WW-BCP (Waste water from bean curd production) without any supplemental nutrients was preliminarily proved to be a potential inexpensive conversion medium.