Design and characterization of immobilized biocatalyst with lipase activity onto magnetic magnesium spinel nanoparticles: A novel platform for biocatalysis.

Abstract

Lipases (EC 3.1.1.3) are very used industrial enzymes but presents drawbacks such as lack of stability, and poor recyclability. Most of these obstacles can be solved by lipase immobilization. The objective of this work was evaluated to magnetic magnesium spinel nanoparticles as support for lipase immobilization by covalent bound. The techniques used for nanoparticles synthesis presented advantages in the size selection of the nanoparticles obtained (60-100 nm). The immobilization of Candida rugosa lipase (CRL) was optimized. The optimal conditions were determined to be pH 3.7, enzyme concentration of 1.1 mg/mL at 4 °C and an ionic strength of 100 mM. The CRL@MgFe2O4 activity obtained was 3.2 times over the starting conditions (4.03 U/mL). The immobilization of the lipase on Fe3O4 was evaluated and compared. The activity of the CRL@MgFe2O4 was 61% higher than CRL@Fe3O4 and 22% higher than free enzyme. CRL@MgFe2O4 improved the lipase stability at alkaline pH, hydrophilic solvent and high temperatures. The thermogravimetric analysis showed that this new biocatalyst was more stable compared to the free enzyme. Additionally, the immobilized lipase was recycled by magnetic force and used in ten catalysis cycles. The performance of the recycle was improved using butanol or Triton X 100 during washing. Finally, CRL@FeMg2O4 showed hydrolysis and synthesis activity. Thus, CRL@FeMg2O4 as a novel biocatalyst generation presents interesting properties for industrial applications.