Effect of polymer matrix on penicillin acylase immobilization on copolymers of butyl acrylate and ethylene glycol dimethacrylate.

Copolymers of butyl acrylate and ethylene glycol dimethacrylate with various degree of crosslinking and aminolysis were used for penicillin acylase immobilization. The amount and activity of the bound protein decreased with the decrease of crosslinking when copolymers having nearly constant degrees of aminolysis were compared. The increase of the carrier amino group content increased the ability to bind the protein (by glutaraldehyde method) without a proportional rise of enzyme activity. The comparative studies of immobilization effect and performance of the derivatives showed 40% crosslinked EGDMA, having an amino group content of 0.67 mmol g-3, to be the carrier of choice. This selected carrier was tested for active protein immobilization by use of crude acylase preparation. It was shown that up to a protein concentration of 9 mg cm-3 in the immobilization mixture the active protein was preferentially bound to the polymer matrix. It was indicated also that the derivative stability was mostly affected by multipoint attachment of the enzyme to the carrier surface.