Candida rugosa Lipase Immobilization on Fe3O4 Coated Carboxyl Functionalised Multiwalled Carbon Nanotubes for Production of Food Flavour Esters

The objective of the study was carboxyl functionalization of Fe3O4 coated multiwalled carbon nanotubes (MWCNTs), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) / N-hydroxysuccinimide (NHS) mediated immobilization of Candida rugosa lipase on MWCNTs through rigid base of dopamine, flexible spacer ethyl methacrylate with adipic acid for improved enzyme characteristics including enhanced dispersion and separation; and use in production of flavour esters ethyl butyrate and butyl butyrate. The immobilized enzyme nanoparticles were characterised by using high resolution transmission electron microscopy (HRTEM), Fourier transmission infrared spectroscopy (FTIR), x-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), zeta potential analysis. Maximum protein loading of 133.83 mg g−1 support and immobilized enzyme activity 4,889.2 U g−1 support was obtained at the optimal time, pH, temperature, protein to support ratio. Immobilized enzyme was tested for pH, thermal, and storage stability. The esterification yields of ethyl butyrate 89.69% and butyl butyrate 91.07% were obtained under optimal conditions. The immobilized enzyme was separated from reaction mixture using the superparamagnetic property and reused for 11 cycles of esterification. Study showed the immobilized enzyme could be used for production of various fruit flavour esters.