Extracellularly-produced siderophores from 7 ARB and a control bacterium PC were collected from their spent growth media. Specifically, the bacteria were grown in modified LB medium for 24 h at 30 °C under 200 rpm shaking condition (Ghosh et al., 2011). Then the spent medium was filtered through 0.2 μM filter to remove bacteria. This filtered fraction of the spent media was again divided into two parts. One half was boiled for 5 min to inactivate enzyme activity and the other half was left intact