Polyphenol Oxidase from Coleus forskohlii: Purification, Characterization, and Immobilization Onto Alginate/ZnO Nanocomposite Materials.

Herein, polyphenol oxidase (PPO) was purified from Coleus forskohlii via a three-step process involving precipitation by (NH4)2SO4, ion exchange chromatography and gel filtration. PPO was purified 15-fold with a total yield of 31% and a specific activity of 3168 U/mg, and the observed molecular weight was 42 kDa. To improve the reusability and stability of the purified enzyme, calcium alginate incorporated with zinc oxide nanoparticles (Ca-ALG-ZnO NPs) was successfully prepared and characterized through scanning electron microscopy and Fourier transform infrared spectroscopy and utilized as a support for PPO immobilization. The immobilization yield and enzyme activity reached 83% and 3950 U/g support, respectively. The results showed that immobilized PPO could be reused ten times while retaining 69% of its original activity. The purified and immobilized PPO exhibited an optimal pH of 7.0 and 7.5 and an optimal temperature of 40 °C and 50 °C, respectively. The purified and immobilized PPO showed Vmax values of 255.75 and 251.89 Units/ml, and Km values of 4.99 and 3.12 mM, respectively. As a result, this work provides an opportunity to understand and manage the influence of the coleus forskohlii PPO enzyme in key immobilization, industrial. Additionally, the results indicated that the Ca-ALG-ZnO NPs used as supports had a significant effect on the enzyme activity and stability of immobilized PPO. [ABSTRACT FROM AUTHOR]