الفهرس | Only 14 pages are availabe for public view |
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. |