Abstract: A dipping method was used to immobilize trypsin onto magnetic core-shell mesoporous molecular sieve (Fe3O4@MCM-41). The effects of immobilization conditions on the recovery of trypsin activity were investigated and immobilized trypsin was analyzed for enzymatic properties and carrier structure. The recovery of trypsin activity reached 55.9% when immobilizing at pH 8.2 and an enzyme loading of 60 mg/g for 4 h. Energy dispersive X-ray spectroscopy (EDS) analysis showed that the immobilized trypsin contained 14% trypsin (calculated on the basis of total nitrogen content). Compared with free trypsin, it showed tolerance to temperature and pH in much wider ranges and better repeated usability and meanwhile, the mesopore structure of the carrier remained good.

Key words: trypsin, magnetic core-shell, mesopore molecular sieve, immobilization