Application of ring-opening metathesis polymerization in study of polymer molecular weight-mediated catalytic properties of immobilized lipase

Recently, significant efforts have been devoted into the study of the effect of hydrophobic supports on the catalytic properties of immobilized lipases. It seems that immobilization lipases on hydrophobic supports is a simple and efficient method to improve the catalytic activity of lipases. In this study, the hydrophobic poly(N-propyl-norbornene-exo-2,3-dicarboximide)s with well-controlled molecular weight were synthesized by the living ring-opening metathesis polymerization, and the lipases from Pseudomonas sp. were then immobilized on these hydrophobic polymer supports through the physical adsorption. The immobilized lipases exhibited higher activity and enantioselectivity for the transesterification of 2-octanol than those of free lipases. Furthermore, we investigated the polymer molecular weight-mediated catalytic properties of immobilized lipases. It was found that the catalytic activity and E value of the immobilized lipases increased with the increase of the polymer molecular weight. At the polymeric molecular weight of about 40kDa, the highest E value (58 at 54.2% of conversion, enantiomeric excess = 99%) was reached. After the molecular weight of polymers getting higher than 40 kDa, catalytic activity and E value of the immobilized lipase decreased. Supported by the Stake Key Development Program of Basic Research of China (Grant No.2007CB808000) and National Natural Science Foundation of China (Grant Nos. 50773028, and 20803028).