Metagenomic analysis of a thermophilic bacterial consortium and its use in the bioremediation of a petroleum-contaminated soil.

Biodegradation is difficult at high temperatures due to the limited capacity of microorganisms to survive and function outside their optimum temperature range. Here, a thermophilic petroleum-degrading consortium was enriched from compost at a temperature of 55 °C. 16S rDNA and metagenomic techniques were used to analyze the composition of the consortium and the mechanisms of degradation. The consortium degraded 17000 mg total petroleum hydrocarbons (TPHs) L−1 with a degradation efficiency of 81.5% in 14 days. The consortium utilized a range of substrates such as n-hexadecane, n-docosane, naphthalene and pyrene and grew well over a wide range of pH (4–10) and salinity (0–90 g L−1). The hydrocarbon-degrading extremophilic consortium contained, inter alia , (relative abundance >1%) Caldibacillus , Geobacillus , Mycolicibacterium , Bacillus , Chelatococcus , and Aeribacillus spp. Metagenomic analysis was conducted to discover the degradation and environmental tolerance functional genes of the consortium. Two alkane hydroxylase genes, alk B and lad A, were found. A microcosm study shows that the consortium promoted the bioremediation of soil TPHs. The results indicate that the consortium may be a good candidate for the high-temperature bioremediation of petroleum-contaminated soils. [Display omitted] • The strain composition of the consortium was stable during degradation. • Bacterial taxa with smaller relative abundances had higher contribution coefficients. • The bacterial consortium promoted the bioremediation of petroleum-contaminated soils. [ABSTRACT FROM AUTHOR]