S. Oda et al., Preparation of methyl ursodeoxycholate via microbial reduction of methyl 7-ketolithocholate in an anaerobic interface bioreactor, J BIOSCI BI, 91(2), 2001, pp. 202-207
An interface bioreactor, which is a device for the microbial transformation
of water-insoluble substrates, was applied to an anaerobic bioconversion f
or the first time. Methyl 7-ketolithocholate [Me-7KLCA] was reduced with th
e human intestinal bacterium Eubacterium aerofaciens JCM 7790 in a convenie
nt anaerobic interface bioreactor using a nutrient agar plate placed in a G
asPak (TM) pouch. The resulting methyl ursodeoxycholate [Me-UDCA] is a prec
ursor of ursodeoxycholic acid, which is used as a cholesterol gallstone-dis
solving agent. The reaction conditions were optimized, and ABCM medium and
dihexyl ether were selected as the best carrier and reaction solvent, respe
ctively. The toxicity of the bile acid esters toward the human intestinal b
acterium was effectively alleviated in the interface bioreactor, in which t
he maximal concentrations of Me7KLCA and Me-UDCA in the dihexyl ether layer
respectively reached to 12.0 and 6.1 g/l.