Bacillus species can serve as a major workhorse to produce biosurfactant for diverse
biotechnological applications. In this study, an indigenous bacterial strain isolated from
petroleum reservoir was found to be a persuasive biosurfactant-producer. Based on
biochemical characteristics, gyrA and 16S ribotyping of the isolate, USTBb, was identified
as Bacillus amyloliquefaciens with 100% identity. Strain USTBb was screened based on
oil-displacement test, emulsification method and ability to reduce surface tension. USTBb
biosurfactant had the ability to decrease the surface tension of water from 72 to 28 mN /m,
with the critical micelle concentration (CMC) of 35 mg/l. To characterize the biosurfactant,
fourier transforms infrared spectroscopy (FT-IR) and energy dispersive X-ray spectroscopy
(EDS) method has been carried out to determine the functional groups and compositional
analysis, respectively. Response surface methodology (RSM) with four variable Central
composite design (CCD), based on a three level, was employed to optimize the
biosurfactant production. The effect of four important growth parameters (temperature, pH,
salinity and crude oil content as carbon course) was studied for enhanced biosurfactant
production. With the optimized method, the relative biosurfactant production expressed as
surface tension reduction was three-fold higher than that obtained in the un-optimized