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Study of Siderophore Formation in Nodule-Forming Bacterial Species

Author Affiliations

  • 1Molecular Sciences and Nanotechnology, College of Engineering and Science, Louisiana Tech University, Ruston 71270, USA
  • 2 Department of Biotechnology, National Institute of Technology, Raipur, 492010, INDIA

Res.J.chem.sci., Volume 2, Issue (11), Pages 26-29, November,18 (2012)


Siderophores are potent ferric ion chelators produced by microbes like bacteria and fungi during iron stress. The objective of this study was to verify the siderophore-production in nodule- forming bacteria and then to compare them with pure cultures of Rhizobium meliloti bacteria. It was achieved by inoculating nodule-forming bacteria in YEM media followed by Chrome Azurol Sulfonate (CAS) assay, a universal siderophore detection method. Formation of orange halos in blue agar plates confirmed the CAS assay. Comparison of diameter of halos with the orange halos of pure strain revealed that the former were less effective in siderophore production. The detergent HDTMA (Hexadecyltrimethylammonium bromide) also appeared to be toxic for some isolates as indicated by negligible growth of the culture. This specificity of different bacterial strains towards siderophore formation and further chelation can be used as a model for identification studies of many human pathogenic bacteria and further to find a classic microbial species for iron-related poisoning.


  1. Neilands J.B., Siderophores: Structure and Function of Microbial Iron Transport Compounds, J.Bio.Chem., 270(45), 2672326726 (1995)
  2. Guan L.L., Kanoh K. and Kamino K., Effect of Exogenous Siderophores on Iron Uptake Activity of Marine Bacteria under Iron-Limited Conditions, App. & Env. Microbio., 67(4), 1710-1717 (2001)
  3. Louden B.C., Haarmann D. and Lynne A.M., Use of Blue Agar CAS Assay for Siderophore Detection, J. Microbio. Bio. Edu., 12(1), 51-53 (2011)
  4. Gottfred N.P.A., Christie B.R. and Jordan D.C., Use of the Chrome Azurol S Agar Plate Technique To Differentiate Strains and Field Isolates of Rhizobium leguminosarum biovar trifolii, App. Env. Microbio., 55(3), 707-710 (1989)
  5. Arora N.K., Kang S.C. and Maheshwari D.K., Isolation of siderophore-producing strains of Rhizobium meliloti and their biocontrol potential against Macrophominaphaseolina that causes charcoal rot of groundnut, Current Sci., 81(6), 673-677 (2001)
  6. Arora N.K., Kumar V. and Maheshwari D.K., Isolation of both fast and slow growing Rhizobia effectively nodulating a medicinal legume, Mucunapruriens,Symbiosis, 29, 121137 (2000)
  7. Dubey R.C., Maheshwari D.K., Kumar H. and Choure K., Assessment of diversity and plant growth promoting attributes of rhizobia isolated from Cajanus cajan L.,African J. Biotech., 9(50), 8619-8629 (2010)
  8. Schwyn B. and Neilands J.B., Universal Chemical Assay for the Detection and Determination of Siderophores, Ana. Biochem, 160,47-56 (1987)
  9. Krey W.B., Siderophore Production by Heterotrophic Bacterial Isolates from the Costa Rica Upwelling Dome, (2008)
  10. Guan L.L. Onuki H. and Kamino K., Bacterial Growth Stimulation with Exogenous Siderophore and Synthetic Acyl Homoserine Lactone Autoinducers under Iron-Limited and Low-Nutrient Conditions, App. & Env. Microbio., 66(7), 2797-2803 (2000)