Degradation of crude oil (Escravos light) by Pseudomonas strains isolated from poultry droppings and cow dung

Abstract

Poultry manure and cow dung have been established as potential material for the bioremediation of petroleum polluted sites, with emphasis on nutrient addition. Our aim was to isolate from poultry droppings and cow dung bacteria with ability to degrade petroleum hydrocarbons. Bacteria were isolated from poultry droppings and cow dung by continuous enrichment and vapor transfer techniques. Petroleum utilization by each isolate was confirmed in carbon free medium containing Escravos crude oil (1%). The two best isolates were selected for further study. Isolates were identified by Analytical Profile Index (API). Antibiotic sensitivity was determined by multidisc. Growth was assayed in broth culture by plate count. Residual oil was determined by Gas Chromatography equipped with Flame Ionisation detector (GC-FID). The isolates were putatively identified as Pseudomonas putida (MP2) and Pseudomonas sp. (MC4). Both isolates were susceptible to ciprofloxacin and chloramphenicol and tarivid. They resisted amoxicillin and gentamycin, augmentin, sparfloxacin and septrin. The growth rates were 0.17 and 0.23/day for strains MP2 and MC4 respectively, while the organisms degraded 88.39% and 89.06 % of crude oil respectively in 20 days. Aliphathic hydrocarbons in the range C11 to C22 were mostly reduced to less than 20%, while C22 – C26 disappeared completely within the same period in both cases. Bacteria capable of extensive degradation of Escravos crude oil were isolated from poultry droppings and cow dung. Such isolates could be veritable candidates for bioaugmentation of hydrocarbon polluted environmental compartments.