title: Substrate dependent in vitro antifungal activity of Bacillus sp strain AR2.
abstract: BACKGROUND
  Biosurfactants are a structurally diverse group of secondary metabolites with lots of potential to serve mankind. Depending upon the structure and composition they may exhibit properties that make them suitable for a particular application. Structural and compositional diversity of biosurfactant is unambiguously substrate dependent. The present study investigates the qualitative and quantitative effect of different water soluble carbon source on the biosurfactant produced by Bacillus amylofaciens strain AR2.
  
  
  RESULTS
  Strain AR2 produced lipopeptide type biosurfactant while growing on water soluble carbon sources. Maximum biosurfactant production was observed in the sucrose supplemented minimal salt medium (MSM). Strain AR2 exhibited carbon source dependent surface tension reduction in the range of 30-37 mN/m, critical micelle concentration (CMC) in the range 80-110 mg/l and emulsification index (EI24 kerosene) in the range of 32-66%. In dextrose, sucrose and glycerol supplemented MSM, strain AR2 produced lipopeptides as a mixture of surfactin, iturin and fengycin. However, in the presence of maltose, lactose and sorbitol only iturin was produced. This substrate dependent compositional variation in the lipopeptides significantly influenced antifungal activity. Lipopeptides produced by strain AR2 while growing on sucrose and dextrose based MSM was observed to be most efficient as an antifungal agent.
  
  
  CONCLUSIONS
  These results suggest that carbon source provided for the growth and biosurfactant production not only influences the yield but also the type of biosurfactant. Sucrose is the most suitable carbon source for production of lipopeptide biosurfactant with antifungal activity.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Singh
authors.forename: Ria
authors.initials: R
authors.lastname: Rautela
authors.affiliation: Institute of Microbial Technology, Sector 39 A, Chandigarh 160036, India. ssc@imtech.res.in.
authors.forename: Swaranjit Singh
authors.initials: SS
authors.lastname: Cameotra
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D001407:Bacillus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005990:Glycerol / Q000378:metabolism / Q000494:pharmacology; D007785:Lactose / Q000378:metabolism / Q000494:pharmacology; D055666:Lipopeptides / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry; D008320:Maltose / Q000378:metabolism / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000096:biosynthesis / Q000737:chemistry; D013012:Sorbitol / Q000378:metabolism / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D013395:Sucrose / Q000378:metabolism / Q000494:pharmacology; D013500:Surface Tension / Q000187:drug effects; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D055666:Lipopeptides; D010456:Peptides, Cyclic; D013501:Surface-Active Agents; C049972:fengycin; C009365:surfactin peptide; D013012:Sorbitol; D013395:Sucrose; D008320:Maltose; D005947:Glucose; D007785:Lactose; D005990:Glycerol