Study of target spacing of thermo-sensitive carrier on the activity recovery of immobilized penicillin G acylase.

The immobilized penicillin G acylase (PGA) is an important industrial catalyst, the activity recovery rate of it directly affects enterprise efficiency. How to improve the enzyme activity recovery rate has been a research focus in this field. Based on the above problems, this work further improved the activity recovery rate by adjusting the target spacing for the first time. Glycidyl methacrylate (GMA) was used as the immobilized target and methyl methacrylate (MMA) as the copolymer monomer. According to the copolymer composition equation of P(MMA-co-GMA), the thermo-sensitive copolymers, PDEA-b-PHEMA-b-P(MMA-co-GMA) with different target spacings, were synthesized rapidly and efficiently via reversible addition-fragmentation chain transfer (RAFT) polymerization method. The error range between the theoretical and actual values of MMA and GMA in the copolymers carrier was (0-4)%, which demonstrated that the reliability of using composition equation to accurately and quickly synthesize copolymers with specific spacing. Studies on the thermo-sensitive showed that the low critical solution temperature (LCST) of the copolymer carrier decreased with the increase of hydrophobic monomer. Most importantly, the activity recovery rate increased with the increase of target spacing, and when the molar ratio of MMA to GMA in the copolymer was 8.75:1, the recovery of activity of immobilized PGA could be up to 63.50%, which was 21.70% higher than that of pure GMA. This work provided an important idea for improving the activity of immobilized PGA.