The application of hydrocarbonoclastic bacteria for the bioremediation of weathered crude oil

Hydrocarbon waste, including crude oil residues in tank bottoms represents an ongoing and growing environmental problem throughout the world as they are particularly persistent within the environment and have the potential to induce a vast array of serious negative health effects for all biological entities. Bioremediation offers a sustainable treatment that reduces the levels of a pollutant present in a soil, for example to sub-toxic concentrations or brings them in line with compliance criteria for safe use or for disposal. In so doing, the risk following release to the environment is ameliorated. The aim of this study was to assess the potential of a hydrocarbonoclastic bacterial consortium, isolated from previously contaminated environments to both survive in contaminated environments and degrade weathered crude oil. Significant changes in the waste oil occurred through incubation with the microbial consortia including, emulsification, loss of viscosity and reduced hydrocarbon content, particularly in the high carbon chain (C20-C70 region). Profiling of the microbial community using denaturing gradient gel electrophoresis confirmed the influence of the addition of the microbial consortia on enhanced diversity of the microflora. Sequence identity of the individual strains present in the microbial consortia identified Pseudomonas sp. as well as several non-cultured gamma-proteobacteria. The result highlights the potential of hydrocarbonoclastic bacterial consortia for use in bioremediation.