Solubility Studies and Synthesis of Acpheleunh2in Reversed Micellar Systems

The aim of the work presented was to study the precipitation of the dipeptide derivative AcPheLeuNH2 in order to improve its yield and productivity during enzymatic synthesis catalysed by α-chymotrypsin in tetradecyltrimethylammonium bromide (TTAB)/heptane/octanol reversed micelles. AcPheLeuNH2 solubility in reversed micellar solutions was examined, revealing that a decrease in TTAB concentration, water to surfactant ratio (Wao) and octanol concentration in the organic mixture led to a decrease in solubility. In contrast, no significant influence 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 organic phase or the micellar water pool. The synthesis of AcPheLeuNH2 was then carried out using those process conditions that led to the lower solubility values. The activity and stability of α-chymotrypsin, dipeptide yield, selectivity, dipeptide recovery an...