The Diversity Study Of Siderophore Producing Bacterial Isolated From Qingdao Inshore Fish

Siderophore, produced by microorganism, is a kind of small molecule compoundwith chelating iron function, it can maintain a variety of microorganism physiologicalfunctions and normal life activities in low iron environment. Due to low soluble ironconcentration of marine environment, marine microorganisms need more siderophores,compare with terrestrial microbes.Iron metabolic is a very complicated process in fish bodies. Not only to fish butalso to a variety of microorganisms in fish, the iron is precious according to their lifedemand, which make it to be crucial for us to learn the significance of complicatedmarine environment, metabolic balance of marine bacteria as well as ironmicroecological environment in fish bodies, and we could study by researchingdiversity of siderophore producing bacteria in fish. The research also has vasttheoretical and practical significance for the application of marine microorganismresources in the future.In this study, by constructing phylogenetic tree and analyzing16S rDNAsequence,53high-yielding siderophore producing strains (isolated from different kindsof fishes in Qingdao coastal area) are categorized into5groups9genera15species:after analyzed,17strains belong to Cobetia marina, accounting for32.07%of these53strains;5strains belong to Bacillus thuringiensis, accounting for9.43%; theproportions of other species are small and all below8%; bacteria groups have obviousdifferences in different fishes.With iron perchlorate experiment, ferric chloride test, Csaky experiment, Aronwexperiment and copper sulfate full wavelength scanning experiment, siderophore types’ diversity of above53strains was studied. In these53high-yielding siderophoreproducing strains:30strains can produce hydroxamic acids siderophores;16strainscan produce catechol siderophores;7strains can produce carboxylic acids siderophores;8strains can produce both hydroxamic acids siderophores and catechol siderophores;one strain can produce both hydroxamic acids siderophores and carboxylic acidssiderophores; one strain can produce both catechol siderophores and carboxylic acidssiderophores.Strain S-EH-1identified as Pseudoalteromonas nigrifaciens can only produceshydroxamic acids siderophore. Its siderophore expression and production reached73.253%and5.494mg/L respectively. The siderophore produced by strain S-EH-1waspartially purified through XAD-2macroporous resin adsorption and Sephadex LH-20sephadex chromatography. The structure of above siderophore was analyzedpreliminarilly by high performance liquid chromatography and electrospray ionizationelectric ion mass spectrometry (LC-MS) method.