p-Nitrophenol Degradation via 4-Nitrocatechol in Burkholderia sp. SJ98 and Cloning of Some of the Lower Pathway Genes

Abstract

Microbial degradation studies have pointed toward the occurrence of two distinct PNP catabolic pathways in Gram positive and Gram negative bacteria. The former involves 4-nitrocatechol (4-NC), 1,2,4-benzenetriol (BT), and maleylacetate (MA) as major degradation intermediates, whereas the later proceeds via formation of 1,4-benzoquinone (BQ) and hydroquinone (HQ). In the present study we identified a Gram negative organism viz. Burkholderia sp. strain SJ98 that degrades PNP via 4NC, BT, and MA. A 6.89 Kb genomic DNA fragment of strain SJ98 that encompasses seven putatively identified ORFs (orfA, pnpD, pnpC, orfB, orfC, orfD, and orfE) was cloned. PnpC is benzenetriol dioxygenase belonging to the intradiol dioxygenase superfamily, whereas PnpD is identified as maleylacetate reductase, a member of the Fe-ADH superfamily showing NADH dependent reductase activity. The in vitro activity assays carried out with purified pnpC and pnpD (btd and mar) gene products transformed BT to MA and MA to beta-ketoadipate, respectively. The cloning, sequencing, and characterization of these genes along with the functional PNP degradation studies ascertained the involvement of 4-NC, BT, and MA as degradation intermediates of PNP pathway in this strain. This is one of the first conclusive reports for 4-NC and BT mediated degradation of PNP in a Gram negative organism.

The Gene Cluster for para -Nitrophenol Catabolism Is Responsible for 2-Chloro-4-Nitrophenol Degradation in Burkholderia sp. Strain SJ98

“…strain RKJ 800 (12) were reported to degrade 2C4NP via the HQ pathway, whereas Burkholderia sp. strain SJ98 degraded 2C4NP with the formation of PNP, which was further degraded via the BT pathway (13,15). On the other hand, Arthrobacter sp.…”

Visible Light-driven Photoelectrochemical Determination of p-Nitrophenol Based on CdSe Quantum Dots and DNA Composite Film Modified Electrode

“…15 As a widely used industrial compound, p-nitrophenol (PNP) has been listed as a priority pollutant by US Environmental Protection Agency (EPA) due to its toxic effects on humans, animals and plants. 16,17 Particularly, PNP interacting with DNA leads to significant damage to the health of human being. 18 However, the presence of a nitro group in PNP causes this aromatic compound to experience a strong chemical stability and resistance to microbial degradation.…”

Degradation of 4-nitrophenol in presence of heavy metals by a halotolerant Bacillus sp. strain BUPNP2, having plant growth promoting traits

“…Microorganisms are known to neutralize the action of toxic compounds by biotransformation or mineralization. Some members of the genera Arthrobacter, Rhodococcus, Bacillus, Pseudomonas, Bhurkholderia and Serratia are reported for 4-NP degradation (Prakash et al 1996;Kadiyala and Spain 1998 ;Pandey et al 2003;Chauhan et al 2010;Sengupta and Saha 2014). Some of them utilize 4-NP as sole carbon source and some degrade it co-metabolically in presence of carbohydrate source (Jamshidian et al 2013).…”