A New Polymeric Support for Enzyme Immobilization for Biomicroreactors

Preparation of three kinds of the modified polyacrylonitrile supports for enzymes used in microreactors is described. The polyacrylonitrile supports were produced using the phase inversion method, with dimethylformamide as a solvent. For conversion of the cyano groups into the carboxylic ones, the raw supports were treated with sodium hydroxide or, alternatively using a new method, with ammonium persulfate. The modified supports were used for urease immobilization. The comparison of the immobilization effectiveness and activity of the immobilized and free enzyme is presented. The effectiveness of urease immobilization was evaluated by two methods, spectrophotometric and potentiometric with use of the flow-through microreactor. It was stated that the two-layer structure films with the polyvinylpyrrolidone, as well as using of the ammonium persulfate for surface modification, made a significant improvement in efficiency of the enzyme immobilization.