Immobilisation of Candida rugosa Lipase on Aminated Polyethylene/Polypropylene Microfibrous Sheet Modified with Oxirane Group

• Published in: ASM science journal Vol. 11; no. 3; pp. 182 - 200
• Main Authors: Hazimah Akbar Tajudin, Ma'an F Alkhatib, Mohamed Elwathig Saeed Mirghani, Hamzah Mohd Salleh, Mohamed Mahmoud Nasef
• Format: Journal Article
• Language: English
• Published: Academy of Sciences Malaysia 01.12.2018
• ISSN: 1823-6782

An active microfibrous substrate containing aminated brush obtained by radiation-induced grafting of glycidyl methacrylate (GMA) onto a polyethylene/polypropylene (PE/PP) microfibrous sheet followed by amination reaction was prepared and used for immobilization of Candida rugosa lipase under various conditions. The aminated microfibrous sheet was characterized by Fourier-transform infrared spectroscopy (FTIR-ATR) and field emission scanning electron microscope (FESEM). The amine group density on the aminated microfibrous sheet was found to be 3.33 mmol/g. Response surface methodology (RSM) was applied to model and optimize the immobilization  conditions including immobilization time (2-6 h), medium pH (pH 7-9) and enzyme/support ratio (5.0-9.0 mg/cm2). The model generated from RSM was significantly correlated with the studied parameters for the residual activity of the immobilized lipase. The optimum values for immobilization time, medium pH, and enzyme/support ratio were found to be 4.24 h, pH 8, and 8.51 mg/cm2 respectively. The enzymatic activity using p-nitrophenyl palmitate (pNPP) as substrate was 1.4588 U/cm2 under optimum conditions. The pH endurance, storage, and thermal stability of the immobilized lipase were remarkably enhanced. The immobilized lipase can be readily recovered and more than 50% of its activity was retained following 10 cycles. The results of this study suggested that the aminated microfibrous sheet of PE/PP grafted with poly(GMA) is a promising polymer support for enzyme immobilization with high potential for broad biocatalytic applications.