Evidence of p-nitrophenol Biodegradation and Study of Genomic Attributes from a Newly Isolated Aquatic Bacterium Pseudomonas Asiatica Strain PNPG3

A p-nitrophenol (PNP) degrading aquatic bacterial strain PNPG3 was isolated from the Ganges water and was identified as Pseudomonas asiatica based on genome sequence analyses. The optimum catabolic growths for the strain was recorded with 0.5 mM PNP and it could tolerate up to 6 mM PNP. It could carry out biodegradation of PNP through p-benzoquinone (PBQ) and 1, 2, 4-benzenetriol (BT) with concomitant release of nitrite. Genome sequence analysis predicted the presence of all the genes (pdcABC1C2DEFG) responsible for providing the PNP biodegradation phenotype for this strain. Based on homology search, the functional attributes encoded by this gene cluster were predicted to include p-nitrophenol 4-monooxygenase (PdcA), benzoquinone reductase (PdcB), hydroxyquinol 1, 2-dioxygenase (PdcC1), hydroxyquinol 1, 2-dioxygenase large subunit (PdcC2), 4-hydroxymuconic semialdehyde dehydrogenase (PdcD), maleylacetate reductase (PdcE), hydroquinone dioxygenase alpha subunit (PdcF) and putative regulator (PdcG). This is the first report of any representative aquatic strain under Pseudomonas asiatica, having the highest known catabolic PNP utilizing capability from the Ganges water of India to the best of the author’s knowledge, and may find application toward cost-effective bioremediation of PNP-contaminated waterbodies.