Evaluation of M(x)O(y)/fucoidan hybrid system and their application in lipase immobilization process

In this work, new M(x)O(y)/fucoidan hybrid systems were fabricated and applied in lipase immobilization. Magnesium (MgO) and zirconium (ZrO(2)) oxides were used as M(x)O(y) inorganic matrices. In the first step, the proposed oxides were functionalized with fucoidan from Fucus vesiculosus (Fuc). The obtained MgO/Fuc and ZrO(2)/Fuc hybrids were characterized by means of spectroscopic analyses, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance. Additionally, thermogravimetric analysis was performed to determine the thermal stability of the hybrids. Based on the results, the mechanism of interaction between the oxide supports and fucoidan was also determined. Furthermore, the fabricated M(x)O(y)/fucoidan hybrid materials were used as supports for the immobilization of lipase from Aspergillus niger, and a model reaction (transformation of p-nitrophenyl palmitate to p-nitrophenol) was performed to determine the catalytic activity of the proposed biocatalytic system. In that reaction, the immobilized lipase exhibited high apparent and specific activity (145.5 U/g(catalyst) and 1.58 U/mg(enzyme) for lipase immobilized on MgO/Fuc; 144.0 U/g(catalyst) and 2.03 U/mg(enzyme) for lipase immobilized on ZrO(2)/Fuc). The immobilization efficiency was also confirmed using spectroscopic analyses (FTIR and XPS) and confocal microscopy.