INTERNATIONAL JOURNAL OF ENERGY RESEARCH, cilt.40, ss.71-80, 2016 (SCI İndekslerine Giren Dergi)
Pervaporation biocatalytic membrane reactor (PVBCMR) is a key method to profit by the all advantages of enzymes. It is an energy intensive, cost-effective and environmental friendly technique which serves as a reactive separation system. In this study, lipase-loaded biocatalytic sodium alginate membranes were prepared, and they were employed in PVBCMR to synthesize ethyl lactate in mild operation conditions. Lipases, synthesized from Candida antarctica (Calb), Rhizomucor miehei (RM) and Thermomyces lanuginosus (TL), were used as enzyme types. Lipases were entrapped by a thin polymer solution and cross-linked on the top surface of non-porous alginate membrane. Reactions were carried out at 30 degrees C for 6 h, and ethanol : lactic acid molar ratio was used as three. Effects of operation time, lipase type, lipase loading, reaction temperature and initial feed molar ratio were investigated as a function of lactic acid conversion. In order to determine the efficiency of the system, PVBCMR results were compared with results of batch reactor. Membrane productivity and selective property were also determined as function of flux and selectivity. Compared to the batch reactor, at least two times higher acid conversion was achieved by biocatalytic membrane reactor in 6 h. Best results were obtained with C. antarctica-based lipase-loaded membranes with all catalyst loading. After the best lipase type was obtained, effect of temperature and feed molar ratio were investigated with Calb-loaded membrane. In PVBCMR system, 0.68 lactic acid conversion was achieved, while 0.335 lactic acid conversion was obtained in batch reactor at 50 degrees C. It was also seen that the biocatalytic membrane preserved its stability for six runs without a significant activation loss. Copyright (c) 2015 John Wiley & Sons, Ltd.