Biodegradation of organophosphorus pesticide profenofos by the bacterium Bacillus sp. PF1 and elucidation of initial degradation pathway

ABSTRACT

Among the organophosphate pesticides, the wide and indiscriminate use of profenofos (PFF) in agricultural and horticultural crops has resulted in serious environmental and animal health concerns and therefore demands an urgent need to develop a biological solution for its effective removal from the environment. For the bioremediation of PFF, a strain PF1, capable of utilizing profenofos as the sole source of carbon and energy was isolated from the soil samples of apple orchards of Shimla region of Himachal Pradesh, India. Based on the biochemical, FAME, and 16S rRNA gene analysis the bacterium PF1 was identified as Bacillus altitudinis (GenBank: MH986176). The strain was able to degrade 50μg mL⁻¹ PFF up to 93% within 30 days of incubation at 28°C, pH 7.0. A linear regression analysis performed on the data-set revealed the statistical significance of the relationship between the growth of the bacterial population and the degradation of pesticides. The compound 4-Bromo-2-chlorophenol (BCP) was detected as one of the pathway metabolites which further were completely degraded to lower pathway metabolites. A probable PFF degradation pathway has been proposed which follows the path from PFF to BCP and ultimately enters into the TCA cycle. To the best of our knowledge, this is the first report of PFF biodegradation by any Bacillus species of western Himalayan origin exhibiting close phylogenetic association with Bacillus altitudinis. This indigenous bacterium can be useful to bio-remediate the PFF contaminated soil as this pesticide is extensively used in the different horticulture fields in Himachal Pradesh, India.

GRAPHICAL ABSTRACT

KEYWORDS:

• Profenofos pesticide
• Bacillus sp. PF1
• biodegradation
• 4-Bromo-2-chlorophenol
• degradation pathway

Acknowledgments

RM and SV gratefully acknowledged the fellowship provided by the CSIR under this project. Authors also acknowledged Central University of Himachal Pradesh, HP, India for providing the basic research facilities, and Dr. Dharam Singh, Senior Scientist, Molecular and Microbial Genetics Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (IHBT) Palampur, HP, India, and the Director, IHBT, Palampur, HP, India for providing necessary facilities to carry out GC/MS studies. The authors also thank Dr. Ankit Tandon, Assistant Professor, Department of Environmental Sciences, Central University of Himachal Pradesh for his help in statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the Council of Scientific & Industrial Research (CSIR ), New Delhi, Government of India, under the CSIR project [grant number 24(0341)/16/EMR-II].