Studies of optimum conditions for covalent immobilization of Candida rugosa lipase on poly(γ-glutamic acid) by RSM

Poly(γ-glutamic acid) (γ-PGA) is a material of polymer. Immobilization of Candida rugosa lipase (Lipase AY-30) by covalent binding on γ-PGA led to a markedly improved performance of the enzyme. Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were employed to evaluate the effects of immobilization parameters, such as immobilization time (2–6 h), immobilization temperature (0–26 °C), and enzyme/support ratio (0.1–0.5, w/w). Based on the analysis of ridge max, the optimum immobilization conditions were as follows: immobilization time 2.3 h, immobilization temperature 13.3 °C, and enzyme/support ratio 0.41 (w/w); the highest lipase activity obtained was 1196 U/mg-protein.