Biosynthesis, characterization, and antibacterial activity of Ti-doped ZnO (Ti/ZnO) using mediated Aspergillus niger

This study presents a biosynthetic route for TiO₂-doped ZnO (Ti/ZnO) using the primary metabolite component of the Aspergillus niger fungi as a source of the capping agent. The effect of biosynthetic variables based on the extracellular (Ti/ZnO) and intracellular (Ti/ZnO) enzymatic cycles of Aspergillus niger during the 3–4 days growth period was analyzed. The morphological differences between the extracellular and intracellular Ti/ZnO produced were characterized using Fourier Transform Infrared (FTIR) spectroscopy, Ultraviolet-Visible Spectrometry (UV–Vis), X-ray Diffraction (XRD), and Scanning Electron Microscope equipped with Energy Dispersive X-ray spectroscopy (SEM-EDX). Analyzing Ti/ZnO with different biosynthetic variables exhibited the same crystal structure, namely hexagonal Wurtzite, but with different morphology and crystal sizes of 27.42–28.99 nm. Furthermore, Ti/ZnO has a pattern of a rod with a length and diameter of 287–455 nm and 126 - 156 nm, respectively. In vitro antimicrobial activity testing against Staphylococcus epidermidis bacterial cells was performed under exposure to ultraviolet light with the wavelength of λ = 385 nm. The results indicated that the increase in bacterial activity was influenced by the effect of biosynthetic variables based on differences in morphology, size, the shape of Ti/ZnO, enzymatic cycle, and growth time of Aspergillus niger.