Resolution of N-(2-ethyl-6-methylphenyl) alanine via cross-linked aggregates of Pseudomonas sp. Lipase

Pseudomonas sp. Lipase (PSL) immobilized with the method of cross-linked enzyme aggregates (CLEAs) using acetone as the optimal precipitant is investigated. The immobilization efficiency (%) and activity retention (%) of the immobilized lipase (CLEA-PSL) are 70.6 and 45.1%, respectively. In the kinetic resolution of N-(2-ethyl-6-methylphenyl) alanine, CLEA-PSL not only keeps excellent enantioselectivity (E-value > 100) as the free PSL, but also shows higher catalytic activity and thermal stability. CLEA-PSL requires only 12 h to obtain 50% conversion whereas the free PSL needs 48 h; the residual activity of CLEA-PSL and free PSL are respectively 72.2 and 23.3% after incubated 24 h at 60 °C. Furthermore, CLEA-PSL can be re-used through ten cycles and the efficiency loss in activity is found to be only 19.1%.