The production of the rhamnolipid-type biosurfactant was
performed according to method described by Santos et al. [15],
using Pseudomonas aeruginosa PA1, a strain previously isolated
from oil wells [16], preserved in ultrafreezer (80 C) with glycerol
10% (w/v). The pre-inoculum (1 g biomass/L) was cultivated in a
rotary shaker at 30 C and 170 rpm for 40–44 h in medium with the
following composition (g/L): NaNO3 1.0; KH2PO4 3.0; K2HPO4 7.0;
MgSO47H2O 0.2; yeast extract 5.0; peptone 5.0 and glycerol 30.0.
At the end of this period, cells were recovered by centrifugation
(5000 g for 15 min) and used as inoculum (1 g/L) in 1 L erlenmeyer
flasks containing 500 mL of medium with the following composition
(g/L): NaNO3 1.4; KH2PO4 3.0; K2HPO4 7.0; MgSO47H2O
0.2 and glycerol 30.0. Fermentation was conducted at 30 C for
168 h.