Influence of environmental factors on biodegradation of quinalphos by Bacillus thuringiensis

Abstract

BackgroundThe extensive and intensive uses of organophosphorus insecticide—quinalphos in agriculture, pose a health hazard to animals, humans, and environment because of its persistence in the soil and crops. However, there is no much information available on the biodegradation of quinalphos by the soil micro-organisms, which play a significant role in detoxifying pesticides in the environment; so research is initiated in biodegradation of quinalphos.ResultsA soil bacterium strain, capable of utilizing quinalphos as its sole source of carbon and energy, was isolated from soil via the enrichment method on minimal salts medium (MSM). On the basis of morphological, biochemical and 16S rRNA gene sequence analysis, the bacterium was identified as to be Bacillus thuringiensis. Bacillus thuringiensis grew on quinalphos with a generation time of 28.38 min or 0.473 h in logarithmic phase. Maximum degradation of quinalphos was observed with an inoculum of 1.0 OD, an optimum pH (6.5–7.5), and an optimum temperature of 35–37 °C. Among the additional carbon and nitrogen sources, the carbon source—sodium acetate and nitrogen source—a yeast extract marginally improved the rate of degradation of quinalphos.ConclusionsDisplay of degradation of quinalphos by B. thuringiensis in liquid culture in the present study indicates the potential of the culture for decontamination of quinalphos in polluted environment sites.

Plant Growth and Drought Tolerance-Promoting Bacterium for Bioremediation of Paraquat Pesticide Residues in Agriculture Soils

“…Biodegradation under controlled conditions is influenced by multiple factors such as temperature, pH, and pesticide concentration (Gangireddygari et al, 2017). In our study, the B. aryabhattai strain MoB09 showed maximum paraquat degradation at pH 7.0, 30 • C and a paraquat concentration of less than 10 mg/L after 72 h of incubation (Figure 4).…”

Fungal Diversity in Tomato Rhizosphere Soil under Conventional and Desert Farming Systems

“…These microbes significantly share biomass and ecosystem functions in both natural and managed agricultural soils ( Sidorenko et al, 1978 ). Microbial diversity is directly or indirectly affected by cultivation techniques, management practices, crop rotation, soil tillage, animal grazing, plant species and climatic changes ( Acosta-Martínez et al, 2014 ; Chen et al, 2017 ; Gangireddygari et al, 2017 ; Liu et al, 2017 ; Yao et al, 2017 ). Variations in soil temperature, precipitation and soil pH also influence soil fungal diversity.…”

Caracterización de cepas nativas de suelos agrícolas tolerantes a imidacloprid

“…La cepa PSI9 presentó un 99% de identidad con B. thuringiensis, además de la presencia de cristales proteicos bipirámidales observados mediante microscopía óptica (dato no presentado). Esta bacteria es conocida por su uso como agente de control biológico para plagas del área agrícola, forestal y de importancia médica a nivel mundial (Brar et al, 2006), también se han realizado estudios de degradación de insecticidas organofosfatos (Wu et al, 2013;Gangireddygari et al, 2017), piretroides (Chen et al, 2015, Pankaj et al, 2016 por lo que se le considera una bacteria prometedora para la degradación de insecticidas químicos de suelo (Ferreira et al, 2016). Por otra parte B. subtilis se ha reportado en la degradación de organofosforados (Acharya et al, 2015) y organoclorados (Kumar et al, 2014) y a B. aryabhattai como promotora de crecimiento (Lee et al, 2012).…”