The process of microbial transglutaminase (TG) covalent immobilization on an ultrafiltration membrane surface, the optimum immobilization conditions and the characteristics of the enzymatic membrane in a reactor were investigated. The process of TG immobilization on polyethersulfone (PES) membrane surfaces was analyzed by Fourier transform infrared and X-ray photoelectron spectroscopy. The optimal condition for TG immobilization was in pH 5.0 phosphate buffer containing TG (20 U/mL). The immobilized TG had a high affinity for the substrate according to the kinetic parameters and retained 50% activity until the twentieth day. Water contact angle and antifouling tests showed that the hydrophilicity of immobilized-transglutaminase membrane was improved compared with pure PES membrane. The enzyme could maintain relatively high activity under a transmembrane pressure of 0.15 MPa. Moreover, the enzymatic membrane had higher relative membrane flux at 0.15 MPa in a membrane reactor, and could retain its activity in pH 5.0 phosphate buffer and catalysis under 40 °C.
Keywords: Characterization; Modification; Polyethersulfone membrane; Transglutaminase immobilization.
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