In this work, lipase produced from an isolated strain Burkholderia sp. C20 was immobilized on magnetic nanoparticles to catalyze biodiesel synthesis. Core-shell nanoparticles were synthesized by coating Fe 3O 4 core with silica shell. The nanoparticles treated with dimethyl octadecyl [3-(trimethoxysilyl) propyl] ammonium chloride were used as immobilization supporters. The Burkholderia lipase was then bound to the synthesized nanoparticles for immobilization. The protein binding efficiency on alkyl-functionalized Fe 3O 4-SiO 2 was estimated as 97%, while the efficiency was only 76% on non-modified Fe 3O 4-SiO 2. Maximum adsorption capacity of lipase on alkyl-functionalized Fe 3O 4-SiO 2 was estimated as 29.45mgg -1 based on Langmuir isotherm. The hydrolytic kinetics (using olive oil as substrate) of the lipase immobilized on alkyl-grafted Fe 3O 4-SiO 2 followed Michaelis-Menten model with a maximum reaction rate and a Michaelis constant of 6251Ug -1 and 3.65mM, respectively. Physical and chemical properties of the nanoparticles and the immobilized lipase were characterized by Brunauer-Emmett-Teller (BET) analysis, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). Moreover, the immobilized lipase was used to catalyze the transesterification of olive oil with methanol to produce fatty acid methyl esters (FAMEs), attaining a FAMEs conversion of over 90% within 30h in batch operation when 11wt% immobilized lipase was employed. The immobilized lipase could be used for ten cycles without significant loss in its transesterification activity.
All Science Journal Classification (ASJC) codes
- Applied Microbiology and Biotechnology