Abstract

Many environment have limited bioavailable iron, which leads to a variety of response strategies aimed at maintaining iron homeostasis Microorganisms, in particular, have specialized iron uptake system and frequently coordinate the synthesis and up take of iron with other cellular function like motility and biofilm formation. Microorganism produce and release low – molecular – weight compounds called siderophores in to the extracellular medium. these chelators have a high affinity and selectivity for Fe(III), making them a crucial component of an iron acquisition strategy. Sidrophores are often characterized as low – molecular – mass substances that chelate iron. Siderophores are more attracted to ferric iron than the majority of proteins. Through their role as iron-complexing ligands, they scavenge available iron and create a very stable ferric ion complex. This complex is know as Fe-siderophores complex or siderophores –iron ion complex.even if the precursor iron is present below the solubility limit, these siderophores –iron complex can stay in solution because they more soluble. Bacteria siderophres will be classified according to their chemical structure, including hydroxycarboxylates, hydroxamic acids, mixed ligands/hydroxamic acids, catecholates/metabolites, and keto acids/chelated metabolites, as well as their source, including surface-associated chelators on the bacterial envelope and released chelators. Example of siderophores Enterobactin it synthesized by Enterobacteriaceae and Pyoverdine produced by Pseudomonas species. bacteria siderophores have many application in several field, they have important role in bioremediation by removing heavy metal from environment and detection dissolving deleterious drugs and contaminants and in medical care, it help to killing or inhibiting pathogenic bacteria through strategies that limit iron acquisition within the host also as in agriculture it support plant growth via availability of iron that help of development and nutrition it.