Biodegradation of chlorpyrifos pesticide by Meiothermus silvanus DSM 9946 isolated from agricultural runoff

Abstract

Indiscriminate usage of pesticides like chlorpyrifos can lead to extensive pollution and can seriously impact human life. After incubating water collected from agricultural runoff in the Kanchipuram district of Tamil Nadu state, it was observed that only one species could efficiently degrade chlorpyrifos. After performing the degradation studies, it was reported that the species could degrade chlorpyrifos completely within 5 d and could also reduce the chemical oxygen demand levels by 95.33%. The optimised experimental conditions were pH-8.5, input dosage-10 ppm and the temperature was maintained within 33°C–40°C. The species was characterised by performing 16s rRNA and has been identified as Meiothermus silvanus DSM 9946. As this bacteria belong to the Thermus genus it can withstand high temperature and it is chemotrophic indicating that it can acquire its nutrition through chemosynthesis by the oxidation of either organic or inorganic molecule. This specific feature might help in the oxidation/degradation of an organic molecule like pesticide, thus, reducing its toxicity. 2,2-dimethoxybutane, 2-heptanol, 6-amino-2-methyl, undec-ane compounds, 2,6-lutidine 3,5-dichloro-4-dodecylthiol, 2-nonenoic acid and carbromal were the metabolites detected in the degraded samples by gas chromatography–mass spectrometry.