siderophore production
Siderophore production test was conducted with selected isolates; CAS (Chrome Azurole S) agar test method was adopted as reported (Schwyn and Neilands, 1987). Actinomycetes isolates were inoculated on CAS agar plate by spot inoculation using autoclaved tooth pick, incubated at 28 ± 2°C for 4-6 days. After incubation, yellow-orange hollow zone around the bacterial colony was considered positive.