Synthesis of xylitoyl fatty acid monoesters by immobilized lipase in subcritical acetone

The thermostability of immobilized lipase from Candida antarctica in subcritical acetone, which was in the liquid state under pressurized conditions, was examined in the temperature range from 60 to 90 °C. The inactivation process of the enzyme did not obey first-order kinetics and the enzyme activity leveled off after a prolonged incubation. The level depended on the temperature, and the remaining activity at 80 °C was 15.4% after 1.5-h incubation. A reactor system consisting of columns packed with xylitol and the immobilized lipase, which were connected in series, was constructed and operated at 80 °C to continuously produce the xylitoyl fatty acid esters. Xylitoyl laurate, myristate and palmitate were synthesized at the constant conversion of ca. 70%, and the productivities of 512, 519 and 551 g/day/L-reactor, respectively, were realized.