A lipase-catalyzed preparation of ethyl and stearyl esters of chenodeoxycholic acid is described. Stearyl
chenodeoxycholate is a new product and both bile acid esters were prepared through an enzymatic
approach for the first time. The heterologous Rhizopus oryzae lipase, immobilized on two different
supports proved to be an efficient catalyst, even more active than Candida antarctica lipase, in the
esterification reaction using a complex substrate such as a bile acid. The immobilization of the enzyme
on Octadecyl Sepabeads at pH 7 and 25 ◦C was the best choice to catalyze the esterification reaction.
The influence of various reaction parameters, such as nature of the alcohol, alcohol:substrate ratio,
enzyme:substrate ratio, solvent and temperature, was evaluated. Using the response surface methodology
and a central composite rotatable design,the conversion of stearyl chenodeoxycholate was optimized
by means of the study of the effect of enzyme:substrate ratio and alcohol:substrate ratio. The value 20
for ratios (E/S) and (A/S) was predicted as the optimal value to reach the maximum conversion. However,
including economic aspects these ratios can be reduced up to 15. The well-known advantages of biocatalysis
and the activity shown by the immobilized heterologous lipase make the reported procedure a
convenient way to prepare chenodeoxycholic esters