Titanium dioxide nanoparticles fabrication from Parmotrema austrosinense (Zahlbr.) Hale extracts and its antimicrobial efficacy against plant pathogens

Green chemistry adoption in biosynthesis of nanoparticles has revolutionized the realm of phyto-medicine. Li-chens that comprise the symbiotic association of fungi and either algae or cyanobacteria render eco-friendly and biocompatible applications. A plethora of secondary metabolites with redox potentials from lichens have wide applications as bioactive incumbents and bio-indicators of pollution. The present study reports, the synthesis of titanium dioxide nanoparticles (TiO2-NPs) using an ultra-sonicated aqueous extract of the lichen Parmotrema austrosinense (Zahlbr.) Hale. The physico-chemical properties of TiO2-NPs were characterized using UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopic (SEM) techniques. Bio-synthesized TiO2-NPs exhibited an average particle size of 10-80 nm indi-cating structural variability. Phytochemical properties were estimated prior to assessment of antibacterial effi-cacies elicited by the synthesized by testing it against selected bacterial and fungal plant pathogens such as Bacillus subtilis, Erwinia chrysanthemi, Xanthomonas phaseoli, Fusarium oxysporum, Rhizoctonia solani, and Sclero-tium rolfsii respectively using agar well diffusion method. The results revealed that as prepared TiO2 nano -particles from lichens owned significant antimicrobial activity against X. phaseoli and F. oxysporum.