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 H-1 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%.