A supported liquid membrane encapsulating a surfactant-lipase complex for the selective separation of organic acids

We have developed a novel, lipase-facilitated, supported liquid membrane (SLM) for the selective separation of organic acids by encapsulating a surfactant-lipase complex in the liquid membrane phase. This system exhibited a high transport efficiency for 3-phenoxypropionic acid and enabled the selective separation of organic acids due to the different solubilities of the acids in the organic phase and the variable substrate specificity of the surfactant-lipase complex in the liquid membrane phase. We found that various parameters, such as the amount of surfactant-lipase complex in the SLM, the lipase concentration in the receiving phase, and the ethanol concentration in the feed phase, affected the transport behavior of organic acids. The optimum conditions were 5 gL^-1 of the surfactant-CRL complex in the SLM (CRL = lipase from Candida rugosa), 8 gL^-1 of PPL in the receiving phase (PPL = lipase from porcine pancreas), and an ethanol concentration of 50 vol %. Furthermore, we achieved high enantioselective transport of (S)-ibuprofen attributable to the enantioselectivity of the surfactant-CRL complex.