Simple physical adsorption technique to immobilize Yarrowia lipolytica lipase purified by different methods on magnetic nanoparticles: Adsorption isotherms and thermodynamic approach

Abstract

Magnetic nanoparticles (Fe₃O₄) were used for physical adsorption of lipase from Yarrowia lipolytica IMUFRJ 50682. The optimal adsorption conditions were obtained as follows: enzyme/support 19.3 mg/g and temperature of 20 °C for standard protein. High immobilization efficiency of 99% was obtained for 4 mL of crude lipase extract (containing 0.315 mg protein/mL) and 0.02 g of magnetic nanoparticles and this biocatalyst was recycled 30 times with 70% of lipase activity in the end. Purified lipase extracts were also efficiently immobilized and ultrafiltered lipase extract (ULE) and aqueous two-phase system lipase extract (ATPS_LE) when immobilized revealed higher hydrolytic activity in relation to CLE (2.8 and 4.0 times higher, respectively). Broad pH tolerance and high thermostability could be achieved by immobilization on magnetic nanoparticles, with 40% improvement in thermodynamic parameters at 60 °C. Kinetic parameters V_max and K_m were also better for ULE (V_max: 2.3 times higher; K_m 43% reduction) and ATPS_LE (V_max: 3.0 times higher; K_m: 38% reduction) immobilized on magnetic nanoparticles in relation to CLE. These results showed that the immobilization of lipase onto magnetic nanoparticles by physical adsorption is an efficient and simple way to obtain a great catalyst.

Keywords: Immobilization; Lipases; Magnetic nanoparticles; Yarrowia lipolytica.