Abstract:
Bioremediation ofers a viable alternative for the reduction of contaminants from the environment,
particularly petroleum and its recalcitrant derivatives. In this study, the ability of a strain of
Pseudomonas BUN14 to degrade crude oil, pristane and dioxin compounds, and to produce
biosurfactants, was investigated. BUN14 is a halotolerant strain isolated from polluted sediment
recovered from the refnery harbor on the Bizerte coast, north Tunisia and capable of producing
surfactants. The strain BUN14 was assembled into 22 contigs of 4,898,053 bp with a mean GC content
of 62.4%. Whole genome phylogeny and comparative genome analyses showed that strain BUN14
could be afliated with two validly described Pseudomonas Type Strains, P. kunmingensis DSM 25974T
and P. chloritidismutans AW-1T. The current study, however, revealed that the two Type Strains are
probably conspecifc and, given the priority of the latter, we proposed that P. kunmingensis DSM
25974 is a heteronym of P. chloritidismutans AW-1T. Using GC-FID analysis, we determined that
BUN14 was able to use a range of hydrocarbons (crude oil, pristane, dibenzofuran, dibenzothiophene,
naphthalene) as a sole carbon source. Genome analysis of BUN14 revealed the presence of a large
repertoire of proteins (154) related to xenobiotic biodegradation and metabolism. Thus, 44 proteins
were linked to the pathways for complete degradation of benzoate and naphthalene. The annotation
of conserved functional domains led to the detection of putative genes encoding enzymes of the
rhamnolipid biosynthesis pathway. Overall, the polyvalent hydrocarbon degradation capacity
of BUN14 makes it a promising candidate for application in the bioremediation of polluted saline
environments.
