Al-Wasify and Shimaa R. This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract An experimental study was undertaken to assess the efficiency of Pseudomonas aeruginosa, Bacillus subtilis, and Acinetobacter lwoffi isolated from petroleum contaminated water and soil samples to degrade crude oil, separately and in a mixed bacterial consortium. Capillary gas chromatography was used for testing the effect of those bacterial species on the biodegradation of crude oil.
Received Feb 21; Accepted Apr Abstract The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced However, neither cell growth nor rhamnolipid production was observed in the comparative culture system using crude oil as the sole carbon source instead.
These results suggest that Pseudomonas aeruginosa could degrade most of crude oil with direct or indirect addition of rhamnolipid. And this conclusion was further supported by another adsorption experiment, where the adsorption capacity of crude oil by killed cell biomass was negligible in comparison with the biologic activities of live cell biomass.
The traditional treatment of oily wastewater, such as containment and collection using floating booms, adsorption by natural or synthetic materials, etc. So far, biodegradation suggests an effective method.
During biodegradation, crude oil is used as an organic carbon source by a microbial process, resulting in the breakdown of crude oil components to low molecular weight compounds.
However, the bioavailability of weekly soluble hydrophobic compounds for microbial conversion is usually low and thus limits their degradation rate in aqueous medium. The use of surfactants has been found to enhance degradation of crude oil Urum et al.
Among various surfactants, rhamnolipids are considered to be the most in degrading hydrocarbons Itoh and Suzuki, For example, the biodegradation of long-chain alkanes was stimulated by addition of rhamnolipid Wouter and Dick, This facilitated biodegradation is probably due to the increase of cell surface hydrophobicity after extraction of lipopolysaccharides from the cellular envelope by rhamnolipids, which subsequently stimulates uptake via direct contact between cells and hydrocarbon droplets.
Thus, the interaction between addition of rhamnolipid and biodegradation of hydrocarbons seems to be highly specific.
However, it is not known whether biodegradation of more recalcitrant crude oil can be facilitated by addition of rhamnolipid.
Although rhamnolipid was reportedly produced by a bacterium NCC-DSS6 isolated from an acclimated semicontinuous reactor fed with crude oil Chhatre et al. The authors of this paper are not aware of researchers on the interaction between addition of rhamnolipid and biodegradation of crude oil.
The objective of this paper was to evaluate the biodegradation of crude oil by Pseudomonas aeruginosa in laboratory. Pseudomonas aeruginosa is a typical strain for rhamnolipid production and can utilize vegetable oil or glycerol as the sole carbon source.
We investigated the feasibility of crude oil degradation by microbial process, focusing mainly on the effect of rhamnolipid on biodegradation. In spite of this, the adsorption by killed cell mass was presented to provide additional support to reports of biological activities of Pseudomonas aeruginosa during biodegradation of crude oil.
In this work, the biodegradation of crude oil was conducted with the same initial basal mineral salt medium to allow comparison of the different supplements.
This strain produces rhamnolipids. The initial pH was adjusted to 6. The growth curve was measured at specific time period during which a 5 ml sample was taken to assay glycerol, biomass and rhamnolipid concentration.Crude Oil and Hydrocarbons Petroleum, also known as crude oil is formed from fossilized remains of marine plants and animals that settled on the sea floor millions of years ago.
Petroleum consists of a complex mixture of hydrocarbons molecules including parrafins, aromatics, napthenes/ cycloalkanes, alkenes and alkynes. Rates of biodegradation depend greatly on the composition, state, and concentration of the oil or hydrocarbons, with dispersion and emulsification enhancing rates in aquatic systems and absorption by soil particulates being the key feature of terrestrial ecosystems.
Progressive degradation of crude oil tends to remove saturated hydrocarbons first, concentrating heavy polar and asphaltene components in the residual oil. This leads to decreasing oil quality by lowering API gravity while increasing viscosity, sulfur, and metal content.
Microbial biodegradation is the use of bioremediation and biotransformation methods to harness the naturally occurring ability of microbial xenobiotic metabolism to degrade, transform or accumulate environmental pollutants, including hydrocarbons (e.g.
oil), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), heterocyclic compounds (such as pyridine or quinoline), . Crude Oil Crude oil is a complex mixture of hydrocarbon molecules formed over millions of years when the remains of microscopic sea creatures trapped in sediments were .
2 Microbial degradation Microbial degradation is the major and ultimate natural mechanism by which one can cleanup the petroleum hydrocarbon pollutants from the environment  The recognition of biodegraded petroleum-derived aromatic hydrocarbons in marine sediments was reported by[ .