A novel method for biosynthesis of different polymorphs of TiO2 nanoparticles as a protector for Bacillus thuringiensis from Ultra Violet

Elham Jalali,Ebrahim Noroozian,Shahab Maghsoudi

doi:10.1038/s41598-019-57407-6

Elham Jalali, Ebrahim Noroozian + Show 1 more

Open Access

https://doi.org/10.1038/s41598-019-57407-6

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Journal: Scientific Reports	Publication Date: Jan 16, 2020
Citations: 35	License type: open-access

Affiliation: Shahid Bahonar University of Kerman

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

Introduction

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.

Results

Conclusion