Biosurfactant production was detected by surface tension lowering and
emulsifying activities from 10 of these strains grown in an iron-limited salt medium supplemented with high
concentrations of dextrose or mannitol, as well as with naphthalene or phenanthrene. Glycolipid determinations
showed that in cultures of Pseudomonas aeruginosa 19SJ on naphthalene, the maximal productivity of
biosurfactants was delayed compared with that in cultures grown on mannitol. However, when small amounts
of biosurfactants and naphthalene degradation intermediates were present at the onset of the cultivation, the
delay was markedly shortened.