Exploring the biodegradation activity of Priestia aryabhattai 1–3I, a promising chlorpyrifos-degrading strain isolated from a local phosphogypsum landfill

Abstract

The current study emphasizes the potential of the microbial community within phosphogypsum landfills to identify promising microorganisms involved in Chlorpyrifos (CP) biodegradation, an organophosphorus pesticide extensively employed in the agricultural sector. We isolated 26 bacterial strains from CP-enriched phosphogypsum sample contaminated with 100 mg Kg⁻¹ CP and subsequently identified them through 16S rRNA sequencing. Among these isolates, Priestia aryabhattai 1–3I displayed remarkable proficiency in utilizing CP as a sole carbon source. Furthermore, P. aryabhattai 1–3I was found to harbor an oph-encoding gene, a crucial component in the CP degradation pathway, with a highly conserved 694 bp region shared by at least 24 homologous oph bacterial genes. The CP-degrading ability of P. aryabhattai 1–3I was assessed both in liquid medium and soil samples, achieving degradation rates of 95 % and 60 %, respectively, starting from an initial concentration of 100 mg L⁻¹ CP after 4 weeks. This pronounced CP-degrading activity correlated with a rapid and significant increase in oph transcripts and was accompanied by a notable rise in the accumulation of a major protein band with a molecular weight of 39 kDa, consistent with the molecular weight of previously characterized oph proteins. Of particular interest, the toxicity of CP degradation products resulting from both CP-bacterial biodegradation experiments exhibited minimal effects on neural cells, as indicated by acetylcholinesterase (AChE) activity and cell viability, underscoring the safety of CP-metabilties. Our study underscores the exceptional biodegradation capability of P. aryabhattai 1–3I in breaking down CP in soil, highlighting its potential for effective remediation of CP-contaminated environments.