Anti-Biofilm Activity of Biosurfactant Derived from Halomonas sp., a Lipolytic Marine Bacterium from the Bay of Bengal

Halophilic bacteria isolated from sediment samples of five oil drilling sites in the Bay of Bengal (BOB) were screened for their biosurfactant-producing ability and for lipase production. The anti-biofilm activity and decolorization efficacy of the biosurfactant was also evaluated. Of 99 isolates, 31 isolates produced extracellular lipases. The optimum temperature and pH for the maximum enzyme activity were 30 degrees C and 6, respectively, at a salt concentration of 15 g/L. Of the various organic substrates used (rice bran oil, gingelly oil, olive oil, and coconut oil), gingelly oil induced the maximum lipase production at a concentration of 5%. The most promising isolate was identified as Halomonas sp. (BOB-3) based on 16S rRNA ribotyping. Halomonas sp. BOB-3 produced lipase with a specific activity of 7777.78 U/mg of protein along with production (0.172 mg/mL) of the biosurfactant, which was characterized by thin layer chromatography, Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC-MS) analyses. The biosurfactant exhibited an anti-biofilm property with an inhibition of bacterial cell growth by 99.5% (V. cholerae) and 99.8% (S. typhi) at 125 mu g/mL concentration. This is the first report on Halomonas sp. from BOB with lipolytic and biosurfactant-producing ability. The biosurfactant obtained was efficient in decolorization and also inhibited biofilm formation by V. cholerae and S. typhi.