SOLUBILITY STUDIES AND SYNTHESIS OF ACPHELEUNH(2) IN REVERSED MICELLAR SYSTEMS

The aim of the work presented was to study the precipitation of the di peptide derivative AcPheLeuNH(2) in order to improve its yield and pro ductivity during enzymatic synthesis catalysed by alpha-chymotrypsin i n tetradecyltrimethylammonium bromide (TTAB)/heptane/octanol reversed micelles. AcPheLeuhNH(2) solubility in reversed micellar solutions was examined, revealing that a decrease in TTAB concentration, water to s urfactant ratio (W-0) and octanol concentration in the organic mixture led to a decrease in solubility. In contrast, no significant influenc e of buffer molarity and pH was detected. These results were explained by suggesting that the main environment for the solubilization of the dipeptide molecules is the micellar interface rather than the bulk or ganic phase or the micellar water pool. The synthesis of AcPheLeuNH(2) was then carried out using those process conditions that led to the l ower solubility values. The activity and stability of alpha-chymotryps in, dipeptide yield, selectivity, dipeptide recovery and purity were d etermined. Reaction conditions were finally selected that enable a hig her performance of the integrated process, combining high activity and yield (85%) with high recovery (89%) of the dipeptide in the form of a pure precipitate (99%).