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Metabolism of 2-chloro-4-nitrophenol in a gram negative bacterium, Burkholderia sp. RKJ 800.

Arora PK, Jain RK - PLoS ONE (2012)

Bottom Line: On the basis of thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry, chlorohydroquinone (CHQ) and hydroquinone (HQ) were identified as major metabolites of the degradation pathway of 2C4NP.Our studies clearly showed that Burkholderia sp.RKJ 800 degraded 2-chloro-4-nitrophenol via hydroquinone pathway.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biotechnology, Institute of Microbial Technology (CSIR), Chandigarh, India. arora484@gmail.com

ABSTRACT
A 2-chloro-4-nitrophenol (2C4NP) degrading bacterial strain designated as RKJ 800 was isolated from a pesticide contaminated site of India by enrichment method and utilized 2C4NP as sole source of carbon and energy. The stoichiometric amounts of nitrite and chloride ions were detected during the degradation of 2C4NP. On the basis of thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry, chlorohydroquinone (CHQ) and hydroquinone (HQ) were identified as major metabolites of the degradation pathway of 2C4NP. Manganese dependent HQ dioxygenase activity was observed in the crude extract of 2C4NP induced cells of the strain RKJ 800 that suggested the cleavage of the HQ to γ-hydroxymuconic semialdehyde. On the basis of the 16S rRNA gene sequencing, strain RKJ 800 was identified as a member of genus Burkholderia. Our studies clearly showed that Burkholderia sp. RKJ 800 degraded 2-chloro-4-nitrophenol via hydroquinone pathway. The pathway identified in a gram negative bacterium, Burkholderia sp. strain RKJ 800 was differed from previously reported 2C4NP degradation pathway in another gram-negative Burkholderia sp. SJ98. This is the first report of the formation of CHQ and HQ in the degradation of 2C4NP by any gram-negative bacteria. Laboratory-scale soil microcosm studies showed that strain RKJ 800 is a suitable candidate for bioremediation of 2C4NP contaminated sites.

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Ring cleavage inhibition studies using 2,2′-dipyridyl. (a) there is no effect on 2,2′-dipyridyl in degradation of 2C4NP by strain RKJ 800. (b) 2,2′-dipyridyl blocks the degradation of HQ in the degradation of 2C4NP by strain RKJ300, therefore, HQ was accumulated.
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pone-0038676-g007: Ring cleavage inhibition studies using 2,2′-dipyridyl. (a) there is no effect on 2,2′-dipyridyl in degradation of 2C4NP by strain RKJ 800. (b) 2,2′-dipyridyl blocks the degradation of HQ in the degradation of 2C4NP by strain RKJ300, therefore, HQ was accumulated.

Mentions: Generally, ferrous ion is required for enzymatic activity of HQ dioxygenase that cleave HQ to γ-hydroxymuconic semialdehyde [17]. 2,2′-dipyridyl is an inhibitor of ferrous ions which is required for HQ dioxygenase activity [17]. When we have added 2,2′-dipyridyl in the minimal media containing 0.3 mM 2C4NP, 10 mM sodium succinate and 2% inoculums of overnight grown strain RKJ 800, there is no accumulation of HQ suggesting ferrous ions were not involved in HQ dioxygenase activity in strain RKJ 800 (Fig 7a). However, ferrous dependent HQ dioxygenase activity was observed in another 2C4NP degrading bacterium, Rhodococcus imtechensis RKJ300 (control cells). When we have added 2, 2′dipyridyl (1.5 mM) in the minimal media containing 0.3 mM 2C4NP, 10 mM sodium succinate and 2% inoculums of overnight grown cells of gram positive bacterial strain RKJ300, 2,2′-dipyridyl chalets the ferrous ions and HQ accumulated in the media (Fig. 7b).


Metabolism of 2-chloro-4-nitrophenol in a gram negative bacterium, Burkholderia sp. RKJ 800.

Arora PK, Jain RK - PLoS ONE (2012)

Ring cleavage inhibition studies using 2,2′-dipyridyl. (a) there is no effect on 2,2′-dipyridyl in degradation of 2C4NP by strain RKJ 800. (b) 2,2′-dipyridyl blocks the degradation of HQ in the degradation of 2C4NP by strain RKJ300, therefore, HQ was accumulated.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368897&req=5

pone-0038676-g007: Ring cleavage inhibition studies using 2,2′-dipyridyl. (a) there is no effect on 2,2′-dipyridyl in degradation of 2C4NP by strain RKJ 800. (b) 2,2′-dipyridyl blocks the degradation of HQ in the degradation of 2C4NP by strain RKJ300, therefore, HQ was accumulated.
Mentions: Generally, ferrous ion is required for enzymatic activity of HQ dioxygenase that cleave HQ to γ-hydroxymuconic semialdehyde [17]. 2,2′-dipyridyl is an inhibitor of ferrous ions which is required for HQ dioxygenase activity [17]. When we have added 2,2′-dipyridyl in the minimal media containing 0.3 mM 2C4NP, 10 mM sodium succinate and 2% inoculums of overnight grown strain RKJ 800, there is no accumulation of HQ suggesting ferrous ions were not involved in HQ dioxygenase activity in strain RKJ 800 (Fig 7a). However, ferrous dependent HQ dioxygenase activity was observed in another 2C4NP degrading bacterium, Rhodococcus imtechensis RKJ300 (control cells). When we have added 2, 2′dipyridyl (1.5 mM) in the minimal media containing 0.3 mM 2C4NP, 10 mM sodium succinate and 2% inoculums of overnight grown cells of gram positive bacterial strain RKJ300, 2,2′-dipyridyl chalets the ferrous ions and HQ accumulated in the media (Fig. 7b).

Bottom Line: On the basis of thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry, chlorohydroquinone (CHQ) and hydroquinone (HQ) were identified as major metabolites of the degradation pathway of 2C4NP.Our studies clearly showed that Burkholderia sp.RKJ 800 degraded 2-chloro-4-nitrophenol via hydroquinone pathway.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biotechnology, Institute of Microbial Technology (CSIR), Chandigarh, India. arora484@gmail.com

ABSTRACT
A 2-chloro-4-nitrophenol (2C4NP) degrading bacterial strain designated as RKJ 800 was isolated from a pesticide contaminated site of India by enrichment method and utilized 2C4NP as sole source of carbon and energy. The stoichiometric amounts of nitrite and chloride ions were detected during the degradation of 2C4NP. On the basis of thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry, chlorohydroquinone (CHQ) and hydroquinone (HQ) were identified as major metabolites of the degradation pathway of 2C4NP. Manganese dependent HQ dioxygenase activity was observed in the crude extract of 2C4NP induced cells of the strain RKJ 800 that suggested the cleavage of the HQ to γ-hydroxymuconic semialdehyde. On the basis of the 16S rRNA gene sequencing, strain RKJ 800 was identified as a member of genus Burkholderia. Our studies clearly showed that Burkholderia sp. RKJ 800 degraded 2-chloro-4-nitrophenol via hydroquinone pathway. The pathway identified in a gram negative bacterium, Burkholderia sp. strain RKJ 800 was differed from previously reported 2C4NP degradation pathway in another gram-negative Burkholderia sp. SJ98. This is the first report of the formation of CHQ and HQ in the degradation of 2C4NP by any gram-negative bacteria. Laboratory-scale soil microcosm studies showed that strain RKJ 800 is a suitable candidate for bioremediation of 2C4NP contaminated sites.

Show MeSH
Related in: MedlinePlus