Candida cylindracea lipase was immobilized by entrapment in gels formed from photo-crosslinkable prepolymers for synthesis of ethyl butyrate by direct esterification of ethanol and butyric acid in hexane. Enzyme immobilization enhanced the enzyme activity up to 2.8 fold, improved the ester yield, and alleviated alcohol inhibition of the enzyme activity. The hydrophobic gel was better than a hydrophilic one in terms of overall performance, and the entrapped enzyme retained 70% of its initial activity after 15 cycles of batch reaction.