Preparation of stearoyl lactic acid ester catalyzed by lipases from Rhizomucor miehei and porcine pancreas optimization using response surface methodology

<p align="justify">The esterification reaction between stearic acid and lactic acid using Rhizomucor miehei lipase and porcine pancreas lipase was optimized for maximum
esterification using response surface methodology. The
formation of the ester was found to depend on three
parameters namely enzyme/substrate ratio, lactic acid
(stearic acid) concentration and incubation period. The
maximum esteri®cation predicted by theoretical equa-
tions for both lipases matched well with the observed
experimental values. In the case of R. miehei lipase,
stearoyl lactic acid ester formation was found to increase
with incubation period and lactic acid (stearic acid)
concentrations with maximum esteri®cation of 26.9% at
an enzyme/substrate (E/S) ratio of 125 g mol)1. In the
case of porcine pancreas lipase, esteri®cation showed a
steady increase with increase in incubation period and
lactic acid (stearic acid) concentration independent of
the E/S ratios employed. In the case of PPL, a maximum
esteri®cation of 18.9% was observed at an E/S ratio of
25 g mol)1 at a lactic acid (stearic acid) concentration of
0.09 M after an incubation period of 72 h.</p>