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

A <i>p</i>-nitrophenol (PNP) degrading aquatic bacterial strain PNPG3 was isolated from the Ganges water and was identified as <i>Pseudomonas asiatica</i> 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 <i>p</i>-benzoquinone (PBQ) and 1, 2, 4-benzenetriol (BT) with concomitant release of nitrite. Genome sequence analysis predicted the presence of all the genes (<i>pdcABC1C2DEFG</i>) 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 <i>p</i>-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 <i>Pseudomonas asiatica</i>, 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.