Production of Biosurfactant by Bacillus Licheniforms Strain JF-2

Bacillus licheniformis strain JF-2 produces a very effective surfactant under conditions typical of oil reservoirs. We have conducted a systematic investigation of the effects of environmental parameters ( temperature, medium pH and NaCl) on : i) the production of the biosurfactant, ii) formation of fermentation end-products and iii) growth of B. licheniformis in batch cultures. The partially purified biosurfactant from JF-2 was shown to be the most active microbial surfactant found so far and gave an interfacial tensions against decane of 0.016 mN/m. Optimal production of the surfactant was obtained in cultures grown in the presence of 5% NaCl at a temperature of 45ºC and pH7.0. The major fermentation end-products were lactic acid and acetic acid with smaller amount of formic acid and acetoin. Growth and biosurfactant formation were also observed in anaerobic cultures supplemented with a suitable electron acceptor such as NaNO₃.