Immobilization of lipase enzyme onto herbal silver nanoparticles and examination of biochemical parameters of immobilized enzyme

Nanoparticles are useful for immobilization due to their size and physical properties. The present study aimed to synthesize herbal silver nanoparticles (SNPs) to immobilize the lipase from Candida rugosa covalently on the nanoparticles as well as to examine the biochemical parameters of the immobilized enzyme. SNPs were synthesized using Cydonia oblonga leaf extract and were characterized. Lipase enzyme was immobilized on synthesized SNPs and the immobilization efficiency was calculated. The biochemical properties of immobilized and free enzymes, including the temperature effect and pH on enzymatic activity, thermal stability, storage stability, and reusability of the immobilized enzyme were specified. Electron microscopy, DLS measurements, and Raman spectroscopy confirmed the 50 nm SNPs and the immobilization of lipase enzyme on them. The efficiency of lipase enzyme immobilization on nanoparticles was estimated to be 48%. The free enzymes and immobilized enzymes had the highest activity at 37°C and 55°C, respectively. Also, the optimal pH was 7 for the free enzyme and 6 for the immobilized enzyme. A comparison of thermal and storage stability of free and immobilized enzymes suggested that immobilized enzymes had more stability and resistance than free enzymes as they also could be reused up to 12 times. The kinetic parameters of the immobilized enzyme compared to the free enzyme indicated a slight decrease in the maximum rate of the enzyme. Immobilized enzymes can be used in industries and are also very crucial for commercial use as they are cost-effective.