Assessment of Bacterial Diversity of Sandy-Loam Soil Polluted by Hydrocarbons Using 454 Pyrosequencing

The study was conducted on polluted soil from a refitting oil station at Pointe-Noire in Congo. The aim of the work was to study the composition of the soil microbial community. Microbial diversity was assessed using the 454 pyrosequencing. The results showed that microbial diversity was represented by 1986 OTUs assigned to the Bacteria domain with 97% of similarity. However, only 246 OTUs were affiliated with 12 Phyla, 24 Classes, 56 Orders and 85 Families. The Proteobacteria (73%), Chloroflexi (16.85%), Bacteroidetes (2.68%) and Actinobacteria (2.65%) were the most representative bacterial phyla. The dominant classes were Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria, Sphingobacteria. The most abundant orders are represented by Rhizobiales (22.94%), Sphingomodales (7.07%), Caulobacterales (6.68%) and three unknown orders corresponding to 28.96%. Bradyrhizobiaceae (14.10%), Sphingomonadaceae (7.05%) and Caulobacteraceae (6.68%) were the best distributed families in the microbial community. This soil could serve for isolation of microorganism consortia for bioremediation.