Bacterial strains diversity in contaminated soils and their potential for bioremediation of total petroleum hydrocarbons in south west of Iran.

Abstract

The main purpose of this research was investigating of bioremediation potential oily contaminated soils using native bacterial strains in an oil field. In this research, total bacterial consortium were identified in oily soils with sandy loam texture as case and non-contaminated soils as controls during six months. The dominant strains present on contaminated soil were identified by DNA extraction using 16S rDNA gene sequencing via NGS technique and compared with bacteria present in non-contaminated soil as control samples. Furthermore, quantitative variations of bacterial count along with total petroleum hydrocarbons (TPH) removal was performed in oily (case) samples to investigate the relation between TPH removal and changes in bacterial density. The TPH values were determined with gas chromatography equipped with a flame ionization detector (GC-FID). The dominant identified bacteria in oily soil were as follows: Halomonas, Moraxellaceae, Thalassobacillus, Zhihengliuella and Enterobacteriaceae which varied significantly from those identified in control soil. The bacterial diversity was higher in contaminated soil and a TPH removal of 50.9% was observed over a period of six months monitoring. Indigenous bacteria in oil-contaminated soils of an oilfield in south west of Iran were found to be able to degrade Total Petroleum Hydrocarbons. Our results showed that bioremediation of oil-contaminated soils can be implemented without need to amplification of heterogeneous bacteria. Considering sandy loam texture of soil samples, the identified strains of bacteria could be introduced as sufficient consortium for biodegradation of this soils with similar texture.