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Biosynthesis of zinc oxide nanoparticles using bacteria: a study on the characterization and application for electrochemical determination of bisphenol A

Abstract Biosynthesis of zinc oxide nanoparticles was carried out by two bacterial strains namely Lactococcus lactis NCDO1281(T) and Bacillus sp PTCC 1538. The produced particles were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Dispersive X-ray Spectroscopy (EDX) analyses. Pure hexagonal crystalline structure of particles was confirmed by XRD spectra and FTIR analysis confirmed the synthesis of zinc oxide. The SEM analysis revealed that zinc oxide produced by B. sp was nano-rods with an average diameter of 99 nm, whereas L. lactis produced nano-spheres with diameter sizes in the range of 55–60.5 nm. Electrochemical sensors based on the biosynthesized nanoparticles and modified carbon paste electrodes were developed for determination of bisphenol A, among which zinc oxide from B.sp exhibited the better performance than the other one. Bisphenol A (BPA) oxidation peak current was about 144.849 µA at the surface of the electrode which was modified with these nanoparticles that is about 5 times more than that of bare electrode. In order to evaluate the stability of nanoparticles, the powders were tested again after six months, and this time the ZnO nanoparticles produced by L. lactis had a better performance than the zinc oxide from B.sp. BPA oxidation peak current was about 75.82 µA at the surface of the electrode that is about 2.7 times more than that of bare electrode.