Influence of environmental factors on biodegradation of quinalphos byBacillus thuringiensis.
BACKGROUND
The 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.


RESULTS
A 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 beBacillus thuringiensis.Bacillus thuringiensisgrew 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.


CONCLUSIONS
Display of degradation of quinalphos byB.thuringiensisin liquid culture in the present study indicates the potential of the culture for decontamination of quinalphos in polluted environment sites.
Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu, Andhra Pradesh 515 003 India.|College of Agriculture & Environmental Sciences, Department of Agriculture & Animal Health, Florida Science Campus, Corner Christiaan De Wet and Pioneer Avenue, Florida, University of South Africa, Johannesburg, Gauteng, 1710 South Africa.
Venkata Subba Reddy
VSR
Gangireddygari
Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu, Andhra Pradesh 515 003 India.
Praveen Kumar
PK
Kalva
College of Agriculture & Environmental Sciences, Department of Agriculture & Animal Health, Florida Science Campus, Corner Christiaan De Wet and Pioneer Avenue, Florida, University of South Africa, Johannesburg, Gauteng, 1710 South Africa.
Khayalethu
K
Ntushelo
Department of Life Sciences, Universidad de las Fuerzas Armadas-ESPE, Sangolqui, Quito, Ecuador.
Manjunatha
M
Bangeppagari
College of Agriculture & Environmental Sciences, Department of Agriculture & Animal Health, Florida Science Campus, Corner Christiaan De Wet and Pioneer Avenue, Florida, University of South Africa, Johannesburg, Gauteng, 1710 South Africa.
Arnaud
A
Djami Tchatchou
Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu, Andhra Pradesh 515 003 India.
Rajasekhar Reddy
RR
Bontha
16S rRNA gene; B. thuringiensis; Generation time; Quinalphos