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BioMed Research International
Volume 2017 (2017), Article ID 1838072, 8 pages
Research Article

Coliform Bacteria for Bioremediation of Waste Hydrocarbons

Microbiology Program, Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, 13060 Safat, Kuwait

Correspondence should be addressed to Samir Radwan;

Received 30 May 2017; Revised 26 July 2017; Accepted 6 August 2017; Published 10 September 2017

Academic Editor: Sardar Khan

Copyright © 2017 Majida Khanafer et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Raw, domestic sewage of Kuwait City contained about 106 ml−1 colony forming units of Enterobacter hormaechei subsp. oharae (56.6%), Klebsiella spp. (36%), and Escherichia coli (7.4%), as characterized by their 16S rRNA-gene sequences. The isolated coliforms grew successfully on a mineral medium with crude oil vapor as a sole source of carbon and energy. Those strains also grew, albeit to different degrees, on individual -alkanes with carbon chains between C9 and C36 and on the individual aromatic hydrocarbons, toluene, naphthalene, phenanthrene, and biphenyl as sole sources of carbon and energy. These results imply that coliforms, like other hydrocarbonoclastic microorganisms, oxidize hydrocarbons to the corresponding alcohols and then to aldehydes and fatty acids which are biodegraded by β-oxidation to acetyl CoA. The latter is a well-known key intermediate in cell material and energy production. E. coli cells grown in the presence of -hexadecane (but not in its absence) exhibited typical intracellular hydrocarbon inclusions, as revealed by transmission electron microscopy. Raw sewage samples amended with crude oil, -hexadecane, or phenanthrene lost these hydrocarbons gradually with time. Meanwhile, the numbers of total and individual coliforms, particularly Enterobacter, increased. It was concluded that coliform bacteria in domestic sewage, probably in other environmental materials too, are effective hydrocarbon-biodegrading microorganisms.