Bioprospecting of pseudomonas aeruginosa for their potential to produce siderophore, process optimization and evaluation of its bioactivity.

Siderophores produced by Pseudomonas spp . play a vital role in controlling several plant diseases. In this study, two siderophore producing bacterial strains were isolated from waste water sample and labeled them as RM1 and RM2 . Among these two isolates, RM1 strain was found to produce more siderophore and therefore selected for further study. 16s rRNA analysis and biochemical characterization as described in the Bergey’s manual of determinative bacteriology, identified the RM1 strain as Pseudomonas aeruginosa 6A (bc4). Siderophore production was determined by more sensitive and reliable Chrome azurol- S (CAS) method.  Chemical and spectrophotometric assays showed that P. aeruginosa 6A strain produced 99% siderophore units. Two siderophores, hydroxamate (Pyoverdine) and phenol catecholate (pyochelin) were mainly found to be produced by this strain. Different parameters such as temperature, pH, carbon and nitrogen sources were optimized for maximum production of siderophores. Maximum production (95.65%) was observed on succinate medium, pH 7.0 and at 40⁰c temperature. Several amino acids were used as carbon and nitrogen sources. Among them serine resulted in a maximum production of siderophore (99.80% unit). The Pseudomonas spp . were also tested as seed inoculants and found to be very effective in seed germination and plant growth promotion of Glycine max JS-335 plant under pot culture conditions. It also exhibits antifungal activity against Aspergilus spp . In summary, the present study has identified a novel siderophore producing bacterial strain, which can also be used as an antifungal agent.