Fabrication of immobilized Candida rugosa lipase on magnetic Fe3O4-poly(glycidyl methacrylate-co-methacrylic acid) composite as an efficient and recyclable biocatalyst for enzymatic production of biodiesel

The development of a magnetically recyclable immobilized lipase for enzymatic biodiesel production is of great research value to meet the need of green and sustainable development. In this work, the organic copolymer, poly(glycidyl methacrylate-co-methacrylic acid) (poly(GMA-co-MAA)), was encapsulated onto the Fe3O4 nanoparticles, and then Candida rugosa lipase was bound on the magnetic composites through coupling reactions with epoxy and carboxyl groups. The Fe3O4-poly(GMA-co-MAA) composite and immobilized lipase were characterized by several techniques, including enzyme activity assay, FT-IR,XRD,SEM,TEM,XPS,VSM and nitrogen adsorption-desorption techniques. Results revealed that the Fe3O4-poly(GMA-co-MAA) composites were successfully synthesized, and the lipase had been anchored on the magnetic composites with the lipase binding efficiency of 88.7% and activity recovery of 67.3%. The immobilized lipase displayed well-defined structure and good magnetic responsibility with saturation magnetization of 28.73 emu/g, and furthermore showed high catalytic activities to the transesterification of soybean oil. The biodiesel yield of 92.8% was attained through three-step addition of methanol at 40 degrees C with this magnetic biocatalyst. The immobilized lipase is recovered facilely by magnetic separation, still retaining at 79.4% of biodiesel yield after reuse for five cycles, and thus highlighting its great potential in the sustainable production of biodiesel. (C) 2020 Elsevier Ltd. All rights reserved.