Fungi possess remarkable capabilities for metal speciation,dissolution,and mineral formation,which contribute to the production of mycogenic nanostructures.This study explores a green chemistry approach for synthesizi...Fungi possess remarkable capabilities for metal speciation,dissolution,and mineral formation,which contribute to the production of mycogenic nanostructures.This study explores a green chemistry approach for synthesizing silver oxide-doped titanium oxide(Ag_(2)O-doped TiO_(2))bionanocomposite utilizing Trichoderma virens.The light yellowish fungal filtrate transformed into a dark brownish colloidal suspension after reacting with silver nitrate and rutile titanium(IV)oxide.X-ray diffractometry(XRD)unveiled the crystalline structure of the bio-nanocomposite(22.15 nm),showing the coexistence of cubic and rutile tetragonal phases of Ag_(2)O and TiO_(2),respectively.Fourier-transform infrared spectroscopy(FTIR)showed the presence of functional groups of alco-hols,phenols,nitro compounds,and aromatic amines derived from the cultural filtrate of T.virens.Raman analysis revealed vibrational modes corresponding to Ag_(2)O and TiO_(2) nanoparticles.Distinct sharp emission peaks characteristic to Ti,Ag,and O were depicted using energy dispersive X-ray(EDX)analysis.X-ray photo-electron spectroscopy(XPS)confirmed the presence of elemental valence states and binding energies of Ag,Ti,and O in the mycogenic nanocomposite.Field emission scanning electron microscopy(FESEM)revealed ag-gregation of polydispersed Ag_(2)O-doped TiO_(2) bionanocomposite,displaying spherical-and cuboctahedron-shaped nanostructures with rough surfaces.High-resolution transmission electron microscopy(HRTEM)showed the presence of circular-,semi-spherical-,hexagonal-,and polygonal-shaped monodispersed Ag_(2)O NPs,with defined boundaries.The Ag_(2)O NPs were obviously deposited on the sheet-like TiO_(2) NPs.Selected area electron diffraction pattern implied the polycrystallinity of the as-synthesized bionanocomposite.A broad antibacterial spectrum of the prepared bionanocomposite was attained against foodborne pathogenic bacteria;Escherichia coli(12.05 mm),Salmonella enterica(11.26 mm),and Staphylococcus aureus(11.44 mm)and phytopathogenic bac-teria;Clavibacter michiganensis subsp.michiganensis(15.72 mm),C.michiganensis subsp.capsici(10.80 mm),streptomycin-sensitive and-resistant Xanthomonas citri pv.citri(14.11 and 14.53 mm,respectively),and streptomycin-sensitive and-resistant Pectobacterium carotovorum subsp.carotovorum(11.36 and 11.07 mm,respectively)using in vitro Kirby-Bauer method.Minimum inhibitory and minimum bactericidal concentrations were determined via a broth micro-dilution assay.FESEM revealed significant morphological alterations in bacterial cells upon treatment with the bionanocomposite,including deformed shape,rough surface,cell thin-ning,wrinkled cell wall,protrusions,cavitations,and cracks.These findings signify the successful mycosynthesis of Ag_(2)O-doped TiO_(2) bionanocomposite,which acted a potent antibacterial agent against a variety of foodborne and phytopathogenic bacteria,which could be employed in environmental,biomedical,agricultural,and food bio-processing applications.展开更多
基金supported by the 2024 Yeungnam University Research Grant.
文摘Fungi possess remarkable capabilities for metal speciation,dissolution,and mineral formation,which contribute to the production of mycogenic nanostructures.This study explores a green chemistry approach for synthesizing silver oxide-doped titanium oxide(Ag_(2)O-doped TiO_(2))bionanocomposite utilizing Trichoderma virens.The light yellowish fungal filtrate transformed into a dark brownish colloidal suspension after reacting with silver nitrate and rutile titanium(IV)oxide.X-ray diffractometry(XRD)unveiled the crystalline structure of the bio-nanocomposite(22.15 nm),showing the coexistence of cubic and rutile tetragonal phases of Ag_(2)O and TiO_(2),respectively.Fourier-transform infrared spectroscopy(FTIR)showed the presence of functional groups of alco-hols,phenols,nitro compounds,and aromatic amines derived from the cultural filtrate of T.virens.Raman analysis revealed vibrational modes corresponding to Ag_(2)O and TiO_(2) nanoparticles.Distinct sharp emission peaks characteristic to Ti,Ag,and O were depicted using energy dispersive X-ray(EDX)analysis.X-ray photo-electron spectroscopy(XPS)confirmed the presence of elemental valence states and binding energies of Ag,Ti,and O in the mycogenic nanocomposite.Field emission scanning electron microscopy(FESEM)revealed ag-gregation of polydispersed Ag_(2)O-doped TiO_(2) bionanocomposite,displaying spherical-and cuboctahedron-shaped nanostructures with rough surfaces.High-resolution transmission electron microscopy(HRTEM)showed the presence of circular-,semi-spherical-,hexagonal-,and polygonal-shaped monodispersed Ag_(2)O NPs,with defined boundaries.The Ag_(2)O NPs were obviously deposited on the sheet-like TiO_(2) NPs.Selected area electron diffraction pattern implied the polycrystallinity of the as-synthesized bionanocomposite.A broad antibacterial spectrum of the prepared bionanocomposite was attained against foodborne pathogenic bacteria;Escherichia coli(12.05 mm),Salmonella enterica(11.26 mm),and Staphylococcus aureus(11.44 mm)and phytopathogenic bac-teria;Clavibacter michiganensis subsp.michiganensis(15.72 mm),C.michiganensis subsp.capsici(10.80 mm),streptomycin-sensitive and-resistant Xanthomonas citri pv.citri(14.11 and 14.53 mm,respectively),and streptomycin-sensitive and-resistant Pectobacterium carotovorum subsp.carotovorum(11.36 and 11.07 mm,respectively)using in vitro Kirby-Bauer method.Minimum inhibitory and minimum bactericidal concentrations were determined via a broth micro-dilution assay.FESEM revealed significant morphological alterations in bacterial cells upon treatment with the bionanocomposite,including deformed shape,rough surface,cell thin-ning,wrinkled cell wall,protrusions,cavitations,and cracks.These findings signify the successful mycosynthesis of Ag_(2)O-doped TiO_(2) bionanocomposite,which acted a potent antibacterial agent against a variety of foodborne and phytopathogenic bacteria,which could be employed in environmental,biomedical,agricultural,and food bio-processing applications.
