3.3. Biosurfactant production
Biosurfactants are fully or partly extracellular polymers.
They are produced by some microorganisms to make the
uptake of lipophilic compounds easier, since they accumulate
at interfaces with different polarities. This feature
prevents the formation of hydrogen bonds and certain
hydrophobic–hydrophilic interactions, causes molecular rearrangements
and reduces the surface tension, a property
related to the attraction and repulsion forces among
molecules of a fluid (Souza et al., 2014). As a result of low
solubility, bioavailability and high hydrophobicity of certain
aromatic compounds (such as PHE), microorganisms are usually
forced to release biosurfactants to uptake them. Since
this is the case, the surface tension of the culture medium
was measured before and after PHE biodegradation assays.
The results showed that there was a reduction in surface
tension from 73.6mN m−1 to 48.5mN m−1 after the assays