Bioremediation of crude oils / complex mixture of hydrocarbons (CMH) contaminants in seawater by a halotolerant bacterial under aerobic conditions: Enterobacter cloacae, Pseudomonas spp. and Escherichia coli.

Ahmed Ould Boudia

Microbiology Laboratory, Abdelhamid Ibn Badis, POBOX 118, Mostaganem 27000, Algeria

E-mail: boudia1978@hotmail.com

Accepted 02 September, 2013

Abstract

Complex mixture of hydrocarbons CMHs are a class of potentially hazardous chemicals of environmental and health concern. CMHs are one of the most prevalent groups of contaminants found in water and soil. Bioremediation of complex hydrocarbons usually requires the cooperation of more than single species. In this research bio-treatment of CMHs was studied in a liquid-phase reactor using halotolerant marine bacteria isolated from two petroleum contaminated sites in Oran, (i.e. industrial ports and fishing ports of Arzew, Oran Algeria). The potential of remediation the CMH was measuring the amount of oxygen consumed by microbial population, the measuring of COD = CO₂ released from the oxygen consumed during the reaction. This technique involves measuring COD oxidized mineralized to CO₂ and resulting oxygen consumption, cumulative consumption of oxygen associated with the degradation of organic matter. Between three bacterial species previously isolated from seawater was assessed in terms of ability or inability to grow in the presence of CMH and potential to degrade the CMH by Enterobacter cloacae, Pseudomonas spp. and Escherichia coli. The remaining eight: Enterobacter cloacae and Pseudomonas spp. showed tolerance to mineralize the crude oil. After 8 days, two representative bacterial strains Enterobacter cloacae and Pseudomonas spp. were chosen for mineralization and respirometry test, performed to evaluate biodegradability potential of CMH and thy capable of degrading petroleum components and utilize the oil as source of carbon and energy. We note that the higher rate of mineralization of CMH start after one week of incubation. The results of this study revealed that Enterobacter cloacae and Pseudomonas spp., are the most versatile species of bacteria that could utilized petroleum products. However, the most important specie remediation for petroleum in environments is Enterobacter cloacae; it’s become predominant in oil-contaminated marine environment.

Keywords: bioremediation, seawater, Warburg, CO₂, CMHs, Enterobacter cloacae, Pseudomonas spp.