Abstract
Bacillus thuringiensis (Bt) were used for biosynthesis of amorphous TiO2 converted to distinct polymorphs (anatase, rutile, mix) under different temperature conditions. Characterizations of TiO2 nanoparticles were performed by using X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and, energy-dispersive X-ray spectroscopy (EDX) analysis. Stability of five formulations under ultraviolet (UV) radiation with spore viability and mortality test on Ephestia kuehniella Zeller larvae were investigated. TiO2(mix) showed the highest viabilities of 79.76% after exposure to ultraviolet (UVA385 nm), while viabilities of non-protected spores under these conditions were 41.32%. The mortality of TiO2(mix), TiO2(anatase), TiO2(rutile), TiO2(amorphous) and free spore formulations on second-instar larvae of Ephestia kuehniella were 73.76%, 71.24%, 57.12%, 51.32%, and 50.32%, respectively on the 10th day of the experiment. The obtained results suggest that TiO2(amorphous) does not increase Bt resistance, but both phases of TiO2 nanoparticles synthesized (anatase and rutile) through the Bacillus thuringiensis and phase mixture can increase the persistence of Bt to the UV light. Furthermore, the combination of both crystalline phases of TiO2(mix) has the highest performance in improving the Bt resistance.
Highlights
The most widely used microbial insecticides are those based on the bacterial pathogen Bacillus thuringiensis (Bt) used as a prosperous biological insecticide and an alternative to chemical pesticides for many years
Bt is applied to kill many different insects and has been widely for pest control, and a commercial formulation of this has been used as an alternative to chemicals
Sunlight as one of the most important natural environmental stress is known to inactivate the biopesticide preparations based on Bt because of ultraviolet light (UV) radiation
Summary
The most widely used microbial insecticides are those based on the bacterial pathogen Bacillus thuringiensis (Bt) used as a prosperous biological insecticide and an alternative to chemical pesticides for many years. The effect of different polymorphs of TiO2 nanoparticles as a material to increase the persistence of Bt active agents against ultraviolet radiation was investigated. XRD patterns show that the peaks of TiO2(anatase) steadily become sharper and narrower with calcination temperature until T = 1200 °C, at which transition toTiO2(rutile) is completed.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
