الفهرس 
Production of biosurfactant by some bacillus strains
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Abstract
Biosurfactants are valuable microbial amphiphilic molecules (consisting of molecules having a polar water-soluble group attached to a water-insoluble hydrocarbon chain) with effective surface-active and biological properties applicable to several industries and processes. In recent years, natural biosurfactants had attracted attention because of their low toxicity, biodegradability, and ecological acceptability. Bacilli species were tested for their abilities to produce biosurfactants by measuring their emulsification activity, emulsification index, oil displacement test, DROP collapse, spreading over the blood agar plates, microbial oil recovery and bacterial adhesion to hydrocarbons. Also, the effect of different carbon and nitrogen sources, as well as, pH and inoculum size were examined as factors affecting the surfactants biosynthesis. Results revealed that three Bacilli isolates can produce biosurfactant by using waste frying oil as a carbon source and peptone as a nitrogen source. There was an effect for any of the tested factors used in the production of biosurfactants due to the tested three isolates. Three from the isolated bacilli spp. were identified by16S rRNA as Bacillus amyloliquefaciens, Bacillus subtilis and Bacillus megaterium. Stability of biosurfactant against temperature, salinity and pH was tested, and the results showed the stability of biosurfactant produced by three bacilli strains