Previously, we have reported about the isolation and screening
of an efficient biosurfactant-producer strain, Bacillus methylotrophicus
USTBa. This strain grew well using crude oil as a source of
carbon and energy, thus demonstrating its potential as a crude
oil-degrader [18]. The objectives of this work are to optimize critical
environmental parameters for effective biodegradation of
crude oil by the pre-isolated and identified strain of B. methylotrophicus
USTBa and to characterize biosurfactant produced by various
techniques including proton nuclear magnetic resonance
spectroscopy (1H NMR), X-ray diffraction (XRD), thermogravimetry
(TG), and differential scanning calorimetry (DSC). In addition, the
toxicity of biosurfactant is investigated as this is considered as an
important criteria for bioreclamation of oil contaminated soils. In
this study, crude oil was used as a model contaminant because it
is a common environmental pollutant.