Chiral Resolution Of Racemates By Immobilized Lipase

In this paper, immobilized lipases from Candida sp. 99-125 and Rhizopus arrhizus BUCT-11 were achieved by means of sol-gel method, and were used in catalytic resolution of racemic 1-phenylethyl amine for enantiomerically pure (R)- or (S)-N-acetyl-1-phenylethyl amine. A detailed investigation was made on the purification and properties of extracellular lipase from Candida sp. 99-125, the technological conditions of the lipase resolution on 1-phenylethyl amine in organic solvent and the influence of immobilizing conditions to the activity and the enatioselectivity of lipases.The extracellular lipase from Candida sp. 99-125 was purified by ion exchange chromatography and hydrophobic interaction chromatography. This two-step method was simple and easy to carry out the large-scale purification of lipase. The results showed that the specific activity of the purified enzyme was 27200 U·mg^-1 raised by 10.0 times and the activity recovery was 35.5%. Four isoenzymes which had the same molecular weight of 38 kDa and a very close pI between 4 and 6 were obtained by isoelectric focusing in Coomassie brilliant blue staining and Rhodanime B staining. The optimum pH and temperature of the purified enzyme were 8.5 and 40°C respectively. The purified lipase remained upwards 95% activity after incubated for 2 d at 20°C and remained upwards 90% activity after incubated for 15 h at pH 5-8 and 23°C. Fe²⁺, Cu²⁺ salts and SDS had an inhibitory effect on lipase activity, whereas Ca salts, Tween80 and Span60 increased it.The technological conditions of the lipase resolution on 1-phenylethyl...