Siderophore production and polyaromatic hydrocarbon utilization by bacterial isolates from a petroleum contaminated soil

Siderophore production by the bacterial isolates from petroleum contaminated soil was investigated to elucidate their role in polyaromatic hydrocarbon (PAH) utilization. Out of 27 isolates, 11 showed siderophore production on chrome azurol S (CAS) agar plates and 9 isolates, including 4 siderophore producers, could not utilize PAHs like naphthalene, anthracene and phenanthrene as sole source of carbon. Siderophore production did not appear to be necessary for PAH utilization as only one third of the PAH utilizers were siderophore producers. A Gram negative bacterial isolate Pseudomonas strain P5–10 showed growth on naphthalene under iron deficient condition unlike isolate P9, a PAH degrader and siderophore non producer. It showed maximum siderophore production in standard succinate medium compared to nutrient broth and Kings B medium. This study shows that although siderophore production is not essential for PAH degradation, the producers are at an advantage under iron deficient conditions.