Continuous screening, an efficient method for the isolation of oil degrading bacteria from oily sludge

Biodegradation is an efficient, economic and environment-friendly method for the remediation of oil contaminated areas. In this research 17 oil degrading bacteria were isolated from the soils and oily sludge using agar-plate method using crude oil as sole carbon source. Also, a continuous bioreactor was used to selection of the bacterium having maximum specific growth rate. Secondary screening and confirmation of the ability of petroleum degradation was carried out in a medium containing crude oil and 2, 6-dichlorophenol indophenol (DCPIP). The strain a1 (g - , short rods) and strain b2 (g + rods) which were obtained by batch-screening were able to decolorize the DCPIP after 5 days, but strain c1 (g - coccus) obtained by continuous-screening degraded petroleum after 16 h. when the bioreactor was inoculated by same concentrations of a1, b2 and c1, the c1 was remained in steady-state (with μmax 0.0291) and a1 and b2 wash-out.