Biodegradation of Phenanthrene by Klebsiella sp Isolated from Organic Contaminated Sediment

Abstract

Aims: This study report the ability of some bacterial strain to degrade the phenanthrene which is a polycyclic aromatic hydrocarbon and to optimize the condition controlling the phenanthrene biodegradation. Study Design: Collect different petroleum contaminated sediment samples, isolate phenanthrene-degrading bacteria on media supplemented with phenanthrene as a unique carbon source, select and identify the most potent bacterial strain. Finally, some of the most biotic and abiotic parameters were optimized to enhance the bacterial biodegradation of phenanthrene. Place and Duration of Study: The study was performed in Microbial Physiology Lab, Botany & Microbiology Department, Faculty of Science, Al-azhar University, from October 2013 until April 2014. Methodology: Various bacterial strains were isolated on media with phenanthrene (400 ppm) as sole carbon source. The most potent bacterial strain was selected on the basis of their capacity to degrade phenanthrene. Different factors such as pH, temperature, inoculum size, shaking and static condition which affect on the biodegradation of phenanthrene were studied depending on estimation the biodegradation ratio of phenanthrene. Results: The most potent bacterial strain (SB_2.1) which showed the highest biodegradation ratio of phenanthrene was identified as klebsiella sp. on the basis of morphological, physiological, and biochemical characteristics. The results revealed that the optimum parameters for maximum degradation of phenanthrene were observed after 21 days at pH value of 7.0 and temperature of 30°C with shaking speed of 150 rpm and at 2% inoculum concentration. The results showed that, this strain of klebsiella sp degraded approximately 84.9% of phenanthrene at an initial concentration of 400 mg/L under the optimal conditions.