Genome-based characterization of a halotolerant strain, Planococcus antioxidans PAB314, with potential for PAH degradation.

To investigate the intrinsic potential of oil-contaminated saline soils for degrading aromatic hydrocarbons, a halotolerant bacterial strain identified as Planococcus antioxidans PAB314 was isolated and characterized for its hydrocarbon-degrading ability. The genome of P. antioxidans PAB314 was sequenced using next-generation techniques, uncovering a 3,705,003 bp genome with 3,263 coding DNA sequences. Gene ontology analysis identified 2,423 genes, highlighting predominant functions in amino acid transport, metabolism, and general cellular processes. GC-MS analysis of naphthalene degradation revealed salicylate and catechol as breakdown products, consistent with established bacterial degradation pathways. Anthracene degradation produced 3-hydroxy-2-naphthoic acid, 6,7-benzocoumarin, and cis-4-(2-hydroxy-3-naphthyl)-2-oxobut-3-enoate, consistent with documented pathways. Pyrene degradation yielded phenanthrene-4,5-dicarboxylate, phenanthrene-4-carboxylate, 1-hydroxy-2-naphthoic acid, and phthalate, suggesting an initial dioxygenation or monooxygenation at the C-4 and C-5 positions to form hydroxylated intermediates, followed by ring cleavage and decarboxylation. Catabolic genes like alcohol dehydrogenase, ring-cleaving dioxygenase, catechol-2,3-dioxygenase, and aldehyde dehydrogenase were found within the genome, indicating P. antioxidans PAB314's genetic capability to degrade polycyclic aromatic hydrocarbons. This study introduces Planococcus antioxidans PAB314 as a novel halotolerant strain capable of efficiently utilizing and degrading aromatic hydrocarbons with diverse ring structures under high-salinity conditions, providing genomic and biochemical evidence of its degradation potential and underscoring its ecological significance and applicability in the bioremediation of hydrocarbon-contaminated saline environments.