Continuous lipase‐catalyzed production of wax ester using silicone tubing

Enzymatic synthesis of cetyl palmitate was performed in a solvent‐free system at 65°C using immobilized Candida antarctica lipase. Batch reactions at controlled water activity showed that the yield could be increased from 88.8 to 99.1% by decreasing the water activity from 1 to 0.05. A continuous reactor configuration was constructed, where two tubular reactors were run in sequence with a separation container in between, in which the water phase was separated from the wax ester phase. The reactor was run for 1 wk at low flow rate (0.005 g/min) with very good operational stability and a productivity of 7.2 g d−1 using 0.4 g of biocatalyst. The activity of the individual preparations decreased during operation. The first reactor had only 30% activity left after 1 wk of operation whereas the second reactor showed only a 10% decrease. This difference in enzyme stability is a direct result of the different water activity in the two reactors.