Halotolerant bacteria are regarded as effective
oil-scavengers in the polluted saltern and seawater. In this
regard, a halotolerant
Planococcus
was isolated from oilcontaminated
area of Dezful north springs, Iran, due to its
capacity in biosurfactant (BS) production. To facilitate
hydrocarbons degradation, in the current study, the efficiency
of BS production as function of growth rate of the
halotolerant
Planococcus was investigated in the vicinity
of heavy crude oil by emulsification index (E24). Subsequently,
the BS characterization was made by thin-layer
chromatography (TLC), gas chromatography (GC) and
infrared spectra analysis, and the stability was determined
by E24 value measurement over a certain pH (5–9), temperature
(20–100 °C) and salt concentration (0–10 % w/v)
ranges. The BS production was found to be growth-associated.
Detection of a unique band on TLC and GC chromatogram
showed the extensive refining capacity of the BS
purification, using the medium supernatant under acetone
alkaline precipitation followed by oil dissolution from the
sediment by carbon tetrachloride. Accordingly, it was
clarified that the BS ultimately accumulated outside the
cells. The glycolipid quality of the BS was further determined
by the routine chemical characterization on TLC and
by IR spectra analysis. Moreover, there was no protein
detected by lowery total protein assay. Finally, the optimal
temperature, pH and NaCl concentration to reach highest
E24 values (85.7, 77.0, and 79.0 %) were found at
respective 40 °C, pH = 9 and 0 % w/v. Our results
revealed the practically potential of strain Dezful Isolate
for BS large-scale production as environmentally friendly
oil-eliminating agents.
