The optimization of glycidyl methacrylate based terpolymer monolith synthesis: an effective Candida rugosa lipase immobilization support

In this work, the optimization of synthesis of terpolymer monolith based on glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) and additional cross-linkers: trimethylolpropanetriacrylate (TMPTA) or triethylene glycol dimethacrylate (TEGDMA) was performed. Moreover, novel vinyl functionalized cross-linkable polymers: ethanolamine (EA)/methacryloyl (MAC) modified poly (methyl methacrylate) (PMMA), and hydrolyzed poly (ethylene-co-vinyl acetate) copolymer (EVOH) modified with MAC either directly or via ethyl malonyl chloride/EA bridging group (m-EVA) were used as cross-linkable polymer to improve mechanical/elastic properties of the obtained monoliths. Optimization procedure, performed applying response surface methodology (RSM), was focused on the production of materials with improved dimensional stability/integrity and porosity with abundance of epoxide groups capable for immobilization of lipase from Candida rugosa (CRL). Structural characterization of the synthesized monoliths was determined using FTIR, Raman and 1H NMR spectroscopies, while morphology/porosity was determined by SEM technique and image analysis; and mechanical properties by diametral compression testing. The most potential monolith containing m-EVA polymeric cross-linker, i.e. GMA/EGDMA/TEGDMA/m-EVA monolith, was used as CRL carrier in a two-step immobilization process. Enzyme loading and the activity of obtained preparations for various initial enzyme concentrations were monitored after 4 and 48 h of immobilization. The resulting catalysts show high potency in biocatalytic reactions with the highest percentage of retained initial lipase activity of 64.5%.