Covalent immobilization and characterization of Rhizopus oryzae lipase on core-shell cobalt ferrite nanoparticles for biodiesel production

Rhizopus oryzae lipase (ROL) was immobilized on the surface of silica coated amino modified CoFe2O4 nanoparticles and applied for biodiesel production. The results indicated more affinity of the ROL toward its substrate upon immobilization, as revealed by a lower Km value for the immobilized ROL compared to its free counterpart. Intrinsic fluorescence spectroscopy indicated a lower intensity for ROL immobilized on CoFe2O4 nanoparticles. Besides, immobilized ROL steady state anisotropy measurements presented lower values, which implied assembly of ROL molecules on magnetic nanoparticles upon immobilization as well as their restricted rotation upon covalent attachment. Thermal stability analysis revealed improved activity at higher temperatures for the immobilized enzyme compared to its free counterpart. Accordingly, Pace analysis to determine protein thermal stability revealed preservation of the protein conformation in the presence of increasing temperatures upon immobilization on nanoparticles. Finally, ROL immobilized on CoFe2O4 nanoparticles exhibited improved efficiency of biodiesel production in agreement with thermal activity profile. Therefore, the authors suggest application of the lipase molecules immobilized on CoFe2O4 nanoparticles for more efficient biodiesel production. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

Immobilization of Rhizopus oryzae lipase on CoFe2O4 nanoparticles enhances substrate affinity, reduces Km value, and improves activity at higher temperatures. Assembly and restricted rotation of immobilized ROL on CoFe2O4 nanoparticles contribute to enhanced stability of the enzyme.