Immobilization of Candida rugosa lipase on poly (3-hydroxybutyrate-co-hydroxyvalerate): a new eco-friendly support

The overall objective of this study is to evaluate the morphological [scanning electron microscopy (SEM)], physicochemical [differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), chemical composition analysis, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR)], and biochemical properties of Candida rugosa lipase (CRL) immobilized on a natural biopolymer poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) in aqueous solution. CRL was immobilized by physical adsorption with efficiency of 30%. Compared with free CRL enzyme, there were slight changes in immobilized CRL activity as a function of temperature (from 37 degrees C to 45 degrees C), but a similar optimal pH value of 7.0. Inactivation rate constants for immobilized CRL enzyme were 0.009 and 0.334 h(-1), and half-lives were 77 and 2 h at 40 degrees C and 60 degrees C, respectively. Kinetic parameters obtained for immobilized CRL include the Michaelis-Menten constant of K-m = 213.18 mM and maximum reaction velocity of V-max = 318.62 U/g. The operational stability of immobilized CRL was tested repeatedly, and after 12 cycles of reuse, the enzyme retained 50% activity. Based on our results, we propose that PHBV-immobilized CRL could serve as a promising biocatalyst in several industrial applications.