Journal of Bioremediation & Biodegradation

Abstrait

Phylogenetic Characterization and Community Diversity of Hydrocarbon-Utilizing Bacteria in Soil Microcosms Enriched with AromaticHydrocarbons

Ola Olapade A

The phylogenetic identities and community diversity of indigenous bacterial populations in soil microcosms previously enriched with various mono-aromatic including benzene, ethyl-benzene and xylene (BEX) hydrocarbons were investigated using combinations of culture-based microbiological (phenotypic) as well as molecular (16S ribosomal RNA gene sequencing) approaches. A total of 45 bacterial isolates belonging to 5 distinct phyla were phylogenetically characterized among indigenous bacterial populations with putative hydrocarbon-degrading potentials in the soil microcosms. In general, bacterial members belonging to the γ-Proteobacteria (mostly species of Pseudomonas and Acinetobacter) were found to numerically dominate {representing between 60 to 94%} among the isolates from the three BEX-polluted microcosms. While, bacterial members belonging to the β-Proteobacteria (Comamonas and Delftia spp) and Firmicutes (Bacillus spp) were also represented. Results obtained from the community diversity calculations revealed relatively higher species richness in the benzene-spiked soils as compared to the other microcosms. Overall, the differences observed in bacterial phylotypes among the microcosms are probably attributable to the direct effects of the chemical properties of each hydrocarbon pollutant on the indigenous microbial community.