Synthesis of enzyme-enriched zinc oxide nanoparticles using Lantana camara L. fruit extract for detoxification of phenol and derivatives

Abstract

In this study, we evaluated the potential of Lantana camara L. (L. camara L.) fruit extract as a biogenic mediator for the synthesis of enzyme-rich zinc oxide nanoparticles (EZnO) aimed at the detoxification of phenol and its derivatives. The protein extraction yielded a maximum concentration in the 80 % cut fraction, with a protein concentration of 0.96 μg/ml. The highest peroxidase enzyme activity was measured at 41 U/min at 80 % cut using a 250 μg protein concentration, while the highest polyphenol oxidase activity of 7.16 μg/ml was observed in the 40 % cut fraction. The synthesis of EZnO nanoparticles was confirmed through a visible color change and UV–visible spectroscopy with a distinctive absorbance peak at 307. 40 nm. X-ray diffraction (XRD) analysis at 2θ angle indicated the crystalline structure of the nanoparticles, with characteristic peaks corresponding to the planes of the ZnO crystal lattice. Fourier-transform infrared spectroscopy (FTIR) characterization revealed the embedding of the peroxidase enzyme within the nanoparticles, evidenced by absorbance peaks at 1708.62 cm⁻¹ corresponding to amide I, 1604.48 cm⁻¹ corresponding to amide II, and 1380 cm⁻¹ corresponding to amide III. Similarly, the presence of polyphenol oxidase was indicated by absorbance peaks at 3185.83 cm⁻¹ and 2981.41 cm⁻¹. Transmission electron microscopy (TEM) analysis showed the nanoparticles exhibited polydispersity with a size range of 10–100 nm, with an agglomerated morphology, suggesting successful enzyme-nanoparticle hybridization. The histogram was constructed based on the counting of nanoparticles with size which showed highest number of nanoparticles were in the range of between 10 and 20 nm. The BET analysis showed a surface area of 225.1 m²/g. The EZnO nanoparticles demonstrated effective detoxification capabilities, achieving 86 % removal of synthetic phenol, 63 % removal of synthetic 2-chlorophenol, and 69 % removal of their mixture within 24 h. These findings highlights the potential of L. camara L. fruit extract and EZnO nanoparticles for application in the detoxification of hazardous pollutants, offering a sustainable and efficient approach to environmental remediation.