Natural bioremediation of crude oil-contaminated soils by bacterial communities in the hyper-arid soil ecosystem in Arava Valley

Natural bioremediation is widely considered the most desirable procedure for restoration of oil-contaminated soil. The main objective of the present study was to examine the change in bacterial diversity in dryland soils contaminated by oil, using a high-throughput sequencing technique. The Illumina MiSeq high-throughput sequencing technique was used to study the bacterial abundance, diversity, and structural change in oil-contaminated soil in a hyper-arid region. The results showed that soil bacterial abundance and diversity significantly declined following oil pollution. The dominant phyla (i.e., Proteobacteria and Patescibacteria) in the petroleum-contaminated soils, are oil-associated and hydrocarbon-degrading bacteria. The abundance of Proteobacteria phyla is ~ 33 % higher in contaminated soil compared to the non-polluted, control samples. For Patescibacteria phyla it ~ 2.5 % higher in contaminated soil compared to the control samples. The opposite trend was noted for Actinobacteria (~ 8 %), Chloroflexi(~ 12 %), Gemmatimonadetes (~ 3 %) and Planctomycetes (~ 2 %) phyla; their abundance was lower in contaminated soil compared to the control samples. The study results provide new insights for natural bioremediation of oil-contaminated soils, both in terms of academic research and developing management practices of desert soils.