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Conversion mechanism of heptachlor by a novel bacterial strain

Microbial treatment is the preferred method for the remediation of soil and water contaminated by heptachlor. We collected sludge samples from the sewage biological treatment pool of Shaanxi Insecticide Factory in Xi'an, China, which were used as bacteria source. With heptachlor as the substrat...

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Autores principales: Qiu, Liping, Wang, Hu, Wang, Xuntao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9078180/
https://www.ncbi.nlm.nih.gov/pubmed/35539625
http://dx.doi.org/10.1039/c7ra10097c
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author Qiu, Liping
Wang, Hu
Wang, Xuntao
author_facet Qiu, Liping
Wang, Hu
Wang, Xuntao
author_sort Qiu, Liping
collection PubMed
description Microbial treatment is the preferred method for the remediation of soil and water contaminated by heptachlor. We collected sludge samples from the sewage biological treatment pool of Shaanxi Insecticide Factory in Xi'an, China, which were used as bacteria source. With heptachlor as the substrate, at 30–35 °C, an effective microorganism (named strain H) for heptachlor degradation was isolated successfully after a long period of acclimation, screening and purification. Strain H was able to use heptachlor as a carbon source and had a good capacity for biodegradation of heptachlor. Strain H was preliminarily identified as a Gram-negative, short rod-shaped, single-cell bacterial strain that was similar to the genus Escherichia or Shigella, according to the analysis of its morphology and physiological–biochemical characteristics. Then, strain H was further identified as a novel bacterium based on the similarity analysis of its 16S rDNA gene sequence with the sequences logged in the RDP and GenBank databases. The 16S rDNA of this bacterium has never been reported before. When the inoculation volume and the pH were 20% and 7.1–7.6, respectively, the degradation rate of heptachlor can reach more than 88.2% in 130 h, with the initial concentration of heptachlor being 300 μg L(−1) at 30–35 °C. Identification of the metabolites by GC/MS showed that strain H degrades heptachlor via two pathways simultaneously, i.e., pathway (1) hydroxylation at the C1 position of heptachlor to 1-hydroxychlordene followed by epoxidation and dechlorination to chlordene epoxide; and pathway (2) epoxidation at the C2 and C3 positions of heptachlor to heptachlor epoxide, and then heptachlor epoxide was further transformed to chlordene epoxide by dechlorination reaction, or degraded to heptachlor diol by hydrolysis reaction. The biodegradation of heptachlor indicated that heptachlor and its metabolites can be converted into less-toxic small molecular metabolites by a series of reactions such as epoxidation, hydrolysis and dechlorination reactions.
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spelling pubmed-90781802022-05-09 Conversion mechanism of heptachlor by a novel bacterial strain Qiu, Liping Wang, Hu Wang, Xuntao RSC Adv Chemistry Microbial treatment is the preferred method for the remediation of soil and water contaminated by heptachlor. We collected sludge samples from the sewage biological treatment pool of Shaanxi Insecticide Factory in Xi'an, China, which were used as bacteria source. With heptachlor as the substrate, at 30–35 °C, an effective microorganism (named strain H) for heptachlor degradation was isolated successfully after a long period of acclimation, screening and purification. Strain H was able to use heptachlor as a carbon source and had a good capacity for biodegradation of heptachlor. Strain H was preliminarily identified as a Gram-negative, short rod-shaped, single-cell bacterial strain that was similar to the genus Escherichia or Shigella, according to the analysis of its morphology and physiological–biochemical characteristics. Then, strain H was further identified as a novel bacterium based on the similarity analysis of its 16S rDNA gene sequence with the sequences logged in the RDP and GenBank databases. The 16S rDNA of this bacterium has never been reported before. When the inoculation volume and the pH were 20% and 7.1–7.6, respectively, the degradation rate of heptachlor can reach more than 88.2% in 130 h, with the initial concentration of heptachlor being 300 μg L(−1) at 30–35 °C. Identification of the metabolites by GC/MS showed that strain H degrades heptachlor via two pathways simultaneously, i.e., pathway (1) hydroxylation at the C1 position of heptachlor to 1-hydroxychlordene followed by epoxidation and dechlorination to chlordene epoxide; and pathway (2) epoxidation at the C2 and C3 positions of heptachlor to heptachlor epoxide, and then heptachlor epoxide was further transformed to chlordene epoxide by dechlorination reaction, or degraded to heptachlor diol by hydrolysis reaction. The biodegradation of heptachlor indicated that heptachlor and its metabolites can be converted into less-toxic small molecular metabolites by a series of reactions such as epoxidation, hydrolysis and dechlorination reactions. The Royal Society of Chemistry 2018-02-02 /pmc/articles/PMC9078180/ /pubmed/35539625 http://dx.doi.org/10.1039/c7ra10097c Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Qiu, Liping
Wang, Hu
Wang, Xuntao
Conversion mechanism of heptachlor by a novel bacterial strain
title Conversion mechanism of heptachlor by a novel bacterial strain
title_full Conversion mechanism of heptachlor by a novel bacterial strain
title_fullStr Conversion mechanism of heptachlor by a novel bacterial strain
title_full_unstemmed Conversion mechanism of heptachlor by a novel bacterial strain
title_short Conversion mechanism of heptachlor by a novel bacterial strain
title_sort conversion mechanism of heptachlor by a novel bacterial strain
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9078180/
https://www.ncbi.nlm.nih.gov/pubmed/35539625
http://dx.doi.org/10.1039/c7ra10097c
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