Introduction
Bioremediation of contaminated aquatic and soil
environments has arisen as an effective technology, with
a range of advantages compared to more traditional
methods. Bioremediation of waste materials, which
contain hydrocarbons and their derivatives, is based
on the ability of microorganisms to increase their
biomass growing on these substrates and degrading
them to non-toxic products, such as H2O and CO2 [16].
Polycyclic aromatic hydrocarbons (PAHs) extensively
occur as pollutants in soil and water, and are important
environmental contaminants because of their recalcitrance.
These compounds also mean a potential risk
to human health, as many of them are carcinogens
[11]. Their persistence within the ecosystems is due to
their low aqueous solubility and high sorption to soil,
two features that limit their availability for the degrading
microorganisms. Bioemulsifiers have been also
reported as enhancers of hydrocarbon biodegradation
in liquid media, soil slurries and soil microcosms [20].
For instance, the dispersion of octadecane in aqueous
solution is dramatically enhanced by application of
300mg l1 of rhamnolipid biosurfactant [31].