Bioremediation of oily hypersaline soil. Bioremediation of oily hypersaline soil via autochthonous bioaugmentation with halophilic bacteria and archaea

Kuwaiti hypersaline soil samples were oil-contaminated and bioaugmented with autochthonous halophilic hydrocarbonoclastic archaeal and bacterial strains, two each, individually and as consortia. Oil hydrocarbons were drastically reduced in all soil samples, including the unbioaugmented ones, with values ranging from 82.7% to 93%. The number of culturable oil-degrading bacteria increased to a range of 142 to 344 CFUx104 g-1. Although culture-independent analysis showed a high proportion of inoculants at T0, none of them could be cultured throughout the bioremediation procedure. The cultured soil communities were represented by the three major bacterial phyla Actinobacteria, Proteobacteria, and Firmicutes. The archaeal phylum Halobacterota represented <1% of the microbial community's relative abundance, which explains why none of its members were cultured. This study emphasizes the possibility of a relatively large resistant population and a greater diversity of oil-degrading microorganisms, as well as the highly selective impacts of oil contamination on hypersaline soil bacterial communities.