A biofilm is any group of microorganisms in which cells stick to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS).
Biofilm-mediated bioremediation presents a proficient alternative to bioremediation with planktonic microorganisms and are generally associated with microbial hydrocarbons resistance or tolerance. Here we report on the ability of three species of Pseudomonas biofilm-associated cells (P. fluorescens, P. putidaand P. aeruginosa) to degrade gasoline (hydrocarbon mixtures), xylene and benzene (monoaromatic compounds) and cyclohexane (cyclic compounds). Changes in biofilm formation and siderophores production were monitored in the presence of different concentrations of benzene and xylene. All strains were able to synthesize biosurfactant compounds and were able to tolerate aromatic hydrocarbon more than the cyclic compounds. Our results indicated that hydrocarbon mixture or gasoline could be better biodegraded by bacterial consortia; P. aeruginosa exhibited the best tolerance to gasoline but not to benzene and cyclohexane. It is interesting to point out that P. fluorescens was able to use xylene and benzene even though P. putida was incapable to grow on benzene as a carbon source. The application of microbial bioremediation technology for the removal of oil and its derivatives from contaminated environments has received much attention. The use of plant rhizosphere-inhabiting bacteria in the bioremediation of pollutants in soils has been proposed as an efficient way to spread degrading bacteria in contaminated soils. In most oil contaminated sites some highly toxic derivatives like benzene, toluene, and xylene (BTX) are present.
Last date updated on June, 2014