Immobilization of penicillin G acylase on methacrylate polymers.

Macroporous weak cation-exchange methacrylate polymers were synthesized for the immobilization of penicillin G (Pen G) acylase. The role of certain factors such as pore-generating solvent, cross-linking agent, cross-linking density, and comonomer, in enzyme adsorption and expression was studied. Kerosene was a superior pore-generating solvent to paraffin oil. Ethylene glycol dimethacrylate and acrylic acid served as the best cross-linking agent and comonomer, respectively, in the systems studied. 80.3% of the activity of the enzyme adsorbed onto polymer beads prepared with 0.05 mol of acrylic acid (polymer PM-39) was expressed. Properties of the Pen G acylase, immobilized on PM-39 by adsorption and cross-linking with glutaraldehyde (IME-PM-39) were studied. The optimum pH, optimum temperature and Km of Pen G acylase shifted from 8.0 to 7.5-7.8, 50 degrees C to 55 degrees C and 0.038 mol dm-3 to 2.4-3.0 mol dm-3, respectively, as a result of immobilization on PM-39. IME-PM-39 was used repeatedly for 15 cycles in the production of 6-amino penicillanic acid (6-APA).