الفهرس 
Carbohydrate Fermentation testOnly 14 pages are availabe for public view
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Abstract
Thirteen isolates of Azotobacter sp. were isolated from different habitats in
Egypt which were screened for their ability to produce siderophores. Among
thirteen isolates one isolate ASH-4 gave the most production of siderophore on
Chrome azurol sulfonate medium and this isolate was selected for further studies.
The isolate ASH-4 was identified as Azotobacter chroococcum using various
biochemical and 16SrRNA gene sequencing analysis. Hydroxymate siderphores
were extracted and the antagonistic activity of partially purified siderphores was
tested against bacterial pathogens Bacillus subtilis and Salmonella sp., in vitro.
Plackett Burman design was used for screening the factors affecting the
siderophores production, and significant factors were optimized using the
Central Compsite design. Sideophores production by A. chroococcum ASH-4
was studied in an experimental bioreactor. The siderophores being produced by
this strain were hydroxamate type. The results showed that the Azotobacter
chroococcum under study is a good producer of siderophores, which can be
beneficial for its antagonistic activity towards different pathogens as biocontrol
agent.