Effect of pore diameter and cross-linking method on the immobilization efficiency of Candida rugosa lipase in SBA-15.

The influences of pore diameter and cross-linking method on the immobilization efficiency of Candida rugosa lipase (CRL) in a mesoporous material have been investigated. Five kinds of SBA-15 with different pore-sizes (6.8nm, 9.1nm, 13.2nm, 15.6nm and 22.4nm) were chosen as the carrier. The one with pore diameter of 15.6nm was proved to be a more suitable immobilization support than the others, and the loading amount reached 343.6mg/g. To solve the leaching problem of the adsorbed enzyme, chitosan and glutaraldehyde were used as the "bridge unit" and "cross-linking agent", respectively, which were supposed to realize the immobilization of lipase molecules adsorbed on the surface of pores into a mesh-like layer. The experimental results showed that the activities of the immobilized CRL were much higher than that of free lipase and remained 80.5% of the initial activity after 6 cycles in 48h.