In oil contaminated environments the poor carbon source availability, the presence of toxic compounds
like benzene, toluene, and xylene (BTX), and other biotic and abiotic stresses can reduce bacteria viability
and consequently, xenobiotic biodegradation. Selection of bacteria with the capability to tolerate and
degrade monoaromatic compounds, synthesize biosurfactants and accumulate biopolymers that
enhance stress tolerance could be a good approach to find a suitable bioaugmentation agent. In this work
two Pseudomonas strains were isolated from an oil refinery wastewater based on their capabilities to
grow using several hydrocarbons as sole carbon source and to accumulate polyhydroxyalkanoates. Both
strains were able to synthesize rhamnolipids as surfactant compounds. One of these isolates, Pseudomonas
sp. KA, was able to degrade benzene, toluene, and xylene, and to tolerate them at high concentrations.
A molecular screening of the key genes involved in BTX degradation showed that both strains
resulted positive for xylA and xylE genes. Pseudomonas sp. KA was also positive for todC1. The presence of
both TOL and TOD degradation pathways, a rare characteristic in Pseudomonas species, could be useful for
bioremediation purposes.
In oil contaminated environments the poor carbon source availability, the presence of toxic compoundslike benzene, toluene, and xylene (BTX), and other biotic and abiotic stresses can reduce bacteria viabilityand consequently, xenobiotic biodegradation. Selection of bacteria with the capability to tolerate anddegrade monoaromatic compounds, synthesize biosurfactants and accumulate biopolymers thatenhance stress tolerance could be a good approach to find a suitable bioaugmentation agent. In this worktwo Pseudomonas strains were isolated from an oil refinery wastewater based on their capabilities togrow using several hydrocarbons as sole carbon source and to accumulate polyhydroxyalkanoates. Bothstrains were able to synthesize rhamnolipids as surfactant compounds. One of these isolates, Pseudomonassp. KA, was able to degrade benzene, toluene, and xylene, and to tolerate them at high concentrations.A molecular screening of the key genes involved in BTX degradation showed that both strainsresulted positive for xylA and xylE genes. Pseudomonas sp. KA was also positive for todC1. The presence ofboth TOL and TOD degradation pathways, a rare characteristic in Pseudomonas species, could be useful forbioremediation purposes.
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