Characteristics of a mesoporous silicate immobilized trypsin bioreactor in organic media

Mesoporous silicates (MPS) materials are attractive materials for immobilizing proteins/enzymes because of their well ordered structures, large surface areas (up to 1000 m² g^-1), narrow pore size distributions, large pore diameters, and pore volumes. MPS with average pore diameters ranging from 28 to 300 Å were prepared using cationic and nonionic surfactants. The influence of water content, pH, storage, and thermal treatment on the activity of trypsin immobilized onto MPS was investigated. In a range of solvents, the amidolytic activity of immobilized trypsin was higher than that of the lyophilized preparation. Significant increases in k _cat/K_M occurred in propanol, ethanol, methanol, and formamide of 90, 62, 45 and 26, respectively. The observed increases were primarily a result of substantial increases in k_cat.