Conclusion
Isolate B. subtilis B30 produced a potent biosurfactant (lipopep-tide similar to Surfactin), using cheaper mineral salt mediacontaining either glucose or date molasses, which is quite stableunder harsh conditions; gives stable emulsions with wide range ofhydrocarbons; and gave around 17–31% additional recovery of lightor heavy crude oil. Further experiments should be done at higherscale.