Isolation of some benzo(a)pyrene- degrading bacteria from contaminated area in Kirkuk city, Iraq

Abstract

Benzo(a)Pyrene is one of the most important environmental contaminants belongs to high molecular PAHs and listed by USEPA as priority pollutant. It has attracted wide interest due to its carcinogenic activity. In order to isolate and diagnose bacterial species that possess the ability to utilise BaP in Mineral Basal Salt Medium (MBSM), Soil samples were collected from the oil contaminated soils from automobile workshop (washing and greasing cars) sites in Kirkuk city. Iinitial diagnosis of bacterial isolates was done rotine method in addition of Vitek 2 compact system to get quick results and prescription in bacterial isolates identification. The results showed eight bacterial species as follows: Pseudomonas mendocina, Stenotrophomonas maltophilia, Enterobacter cloacae, Cupriavidus pauculus, Klebsiella pneumoniae, Pantoea spp, Acinetobacter haemolyticus, Comamonas testosterone. Anew bacterial genera were recorded in the present study including Cupriavidus pauculus, Pantoea sp, Cupriavidus pauculus and Comamonas testosteroni have the ability to utilize BaP as the only source of carbon and energy. The results of experimental culture to determine CFU/ml of each bacterial isolate referred to highest CFU/ml was recorded for Enterobacter cloacae (2.96×1026 CFU/ml) indicating the highest growth followed by Klebsiella pneumonia (2.92×1024 CFU/ml). There was linear increase in number CFU of cells with increase the incubation time (0, 2, 4, 8, 16 and 32 days). On the day 32 incubation about 74.67% and 67.48 % of BaP were utilize by both E. cloacae and K. pneumonia respectively.