Paddy field soil with prior exposure to chlorpyrifos was chosen for the biodegradation of the pesticide by employing bacteria with special emphasis given to actinomycetes. Actinomycetes are organisms predominantly known for their bioactive compounds, but there is dearth of work pertaining to their role in bioremediation. So this work was carried out to screen for actinomycetes and assess their potential in degradation of the pesticide. Actinobacterial strains were isolated from paddy field soil, with capabilities to degrade chlorpyrifos and its major metabolite 3,5,6-trichloro-2-pyridinol (TCP). Two strains were successfully isolated among which one strain was efficient and was able to tolerate high concentrations of chlorpyrifos. This strain was selected for further investigation; it was identified as Gordonia sp based on 16S rRNA analysis and designated as Gordonia sp JAAS1. The actinobacterial strain was able to degrade 110 mg l-1 of chlorpyrifos within 24 h incubation, and TCP was found to accumulate in the culture medium. However, after 72 h of incubation, TCP was degraded, and finally, diethylthiophosphoric acid (DETP) was obtained. © 2013 The Society for Applied Microbiology.

Jayanthi Abraham

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Vellore Campus

Shanker A

Silambarasan S.

Fulltext

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Letters in Applied Microbiology

The study focuses on the biodegradation kinetics of organophosphate pesticides (OPs), chlorpyrifos and dichlorvos by enriched cultures and its application in pesticide transport models. Pseudomonas aeruginosa and Taonella mepensis were the species identified in dichlorvos enriched culture (DEC) while Pseudomonas aeruginosa and Methylobacterium zatmanii were present in chlorpyrifos enriched culture (CPEC). DEC readily degraded dichlorvos as the sole carbon source at higher concentrations up to 1000 mg/L while CPEC rapidly degraded chlorpyrifos up to 100 mg/L. On addition of 1 g/L C of dextrose, dichlorvos degradation efficiency significantly increased only at higher pesticide concentrations while there was no effect on chlorpyrifos degradation. Cross-feed and mixed-feed studies highlighted that, CPEC degraded dichlorvos as a sole substrate and a mixture of both the pesticides effectively when compared to DEC. Edward inhibition and Haldane inhibition models satisfactorily simulated the biodegradation kinetics of dichlorvos and chlorpyrifos by DEC and CPEC respectively. The biokinetic parameters; maximum specific growth rate (µmax), half saturation constant (KC), yield coefficient (Y) and inhibition concentration (Ki) for the selected pesticides were thus estimated from the best fit biokinetic models. Further, batch determined biokinetic parameters were successfully applied to pesticide transport model and used to simulate breakthrough curves (BTCs) from flow-through pesticide soil column studies. The results indicated that the enriched microbes are promising candidates for insitu bioremediation of contaminated waters and soils. In addition, the estimated biokinetic constants can be used to assess the biodegradation capabilities of the enriched cultures and act as input parameters for transport models. © 2019, © 2019 Taylor &amp; Francis Group, LLC.

Bioremediation Journal

Biodegradation kinetics of dichlorvos and chlorpyrifos by enriched bacterial cultures from an agricultural soil

JAS1 bacterial strain capable of degrading chlorpyrifos and its major metabolite 3,5,6-trichloro-2-pyridinol (TCP) were isolated from paddy field soil. The isolated bacterial strain was characterized using morphological and biochemical analysis, as well as molecular characterization based on 16S rRNA sequence homology which confirmed its identity as Alcaligenes sp. The isolated bacterial strain efficiently degraded 300mg/l of chlorpyrifos within 12h of incubation and TCP was observed to accumulate in the aqueous medium. In soil studies with nutrients amendment along with chlorpyrifos and Alcaligenes sp. JAS1 showed undetectable level of pesticide in 24h, whereas in the absence of nutrients the pesticide was found to be degraded in 48h. Kinetic studies based on various models were carried out and the results showed a very good compliance with the first and pseudo first order models. TCP degradation process by Alcaligenes sp. JAS1 was characterized by the rate constant (k) of 1.364d-1 and the initial concentration was reduced by 50% (DT50) was 0.5d in the aqueous medium. Studies on biodegradation of TCP in soil with nutrients showed that JAS1 strain exhibited efficient degradation with a rate constant of 1.137d-1, and DT50 was 0.6d. In contrast, degradation of TCP in soil without nutrients was characterized by a rate constant of 0.953d-1 and DT50 was 0.7d. © 2012 Taiwan Institute of Chemical Engineers.

Journal of the Taiwan Institute of Chemical Engineers

Kinetic studies on enhancement of degradation of chlorpyrifos and its hydrolyzing metabolite TCP by a newly isolated Alcaligenes sp. JAS1

Biodegradation of chlorpyrifos was studied in mineral medium and soil with a novel fungal strain JAS1 isolated from a paddy field soil. The molecular characterization based on 18S rRNA sequence homology confirmed its identity as Aspergillus terreus. The 300-mg L-1 chlorpyrifos and its major metabolite 3,5,6-trichloro-2-pyridinol (TCP) were completely degraded within 24 h of incubation in the mineral medium. In soil enriched with chlorpyrifos and nutrients (carbon, nitrogen, and phosphorous), A. terreus JAS1 was able to degrade chlorpyrifos and its metabolite TCP (300 mg kg-1 soil) in 24 and 48 h, respectively. The soil was spiked with chlorpyrifos (300 mg kg -1 soil) devoid of nutrients and the fungal strain was capable of degrading both chlorpyrifos and TCP in 24 and 48 h, respectively. The course of the degradation process was studied using high-performance liquid chromatography and Fourier transform infrared analyses. These results showed that the chlorpyrifos-degrading fungal strain had the potential to degrade the pesticide-contaminated agricultural soils even without addition of nutrients. © 2013 Springer Science+Business Media Dordrecht.

Water, Air, & Soil Pollution

Ecofriendly Method for Bioremediation of Chlorpyrifos from Agricultural Soil by Novel Fungus Aspergillus terreus JAS1

Bioresource Technology

Biodegradation of chlorpyrifos and 3,5,6-trichloro-2-pyridinol by Cupriavidus sp. DT-1

PLoS ONE

Biodegradation of Chlorpyrifos and Its Hydrolysis Product 3,5,6-Trichloro-2-Pyridinol by a New Fungal Strain Cladosporium cladosporioides Hu-01

International Biodeterioration & Biodegradation

Chlorpyrifos biodegradation and 3,5,6-trichloro-2-pyridinol production by actinobacteria isolated from soil

Role ofGordoniasp JAAS1 in biodegradation of chlorpyrifos and its hydrolysing metabolite 3,5,6-trichloro-2-pyridinol

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ISSN	0266-8254
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