Immobilization of Lipase from Mucor Miehei Onto Poly (Ethylene) Based Graft Copolymers

Lipase from Mucor miehei was immobilized covalently onto hydrolyzed poly(ethylene)-g.co-hydroxyethyl methacrylate (PE-HEMA). This hydrolysis of the copolymer was achieved using 0.1 M NaOH over different periods of time, under controlled conditions. The graft copolymers and their hydrolyzed equivalents were characterized by scanning electron microscopy (SEM) and by differential scanning calorimetry analysis (DSC). Water sorption studies were undertaken to provide a measure of relative hydrophobicity of the samples.

The lipase immobilization reaction was studied in order to assess the effects of controlling various important parameters. These include the nature of the buffering medium, the time over which the immobilization was allowed to occur, the concentration of the activating and coupling agent used (CMC) and the concentration of enzyme employed during attempts at effective immobilization. The immobilized lipase was used in the hydrolysis of triolein (glycerol trioleate). From this study, the apparent K_M, the optimum pH for hydrolysis and the optimum temperature for hydrolysis were revealed.

The suitability of hydrolyzed poly(ethylene)-g.co-HEMA as a support in the immobilization of lipase was assessed by determination of the amount of lipase coupled to the support and by assessment of the retention of activity of the immobilized lipase after its exposure to the immobilization reagents, procedure and conditions.