Dynamic responses in bioaugmentation of petroleum-contaminated soils using thermophilic degrading consortium HT: Hydrocarbons, microbial communities, and functional genes

Bioaugmentation offers an effective strategy for the bioremediation of petroleum-contaminated soils. However, little is known about petroleum hydrocarbons (PHs) degradation with thermophilic consortium application under high temperature. A microcosm was established to study hydrocarbons degradation, microbial communities and functional genes response using a thermophilic petroleum-degrading consortium HT. The results showed that the consortium HT significantly enhanced PHs degradation, particularly for medium (C16-C21) (87.1 %) and long-chain alkanes (C21-C40) (67.2 %) within 140 days under high temperature. Colonization of HT in the soil exhibited lagged characteristics, with a substantial increase in bacterial genera originated from the HT after 60 days. Additionally, LEfSe analysis indicated that the biomarkers of HT treatment were mainly from the HT consortium. Moreover, functional analysis revealed genes related to n-alkane degradation (AlkB, P450, LadA), alkane utilization regulator (AraC, TetR, GntR), as well as several thermotolerance genes were significantly increased in HT treatment. Additionally, network analysis demonstrated distinct co-occurrence patterns induced by nutrient addition and exogenous consortium, with the latter strengthening interactions and stability of bacterial networks under high temperature. This study represents pioneering investigation into the effects of exogenous thermophilic consortium on petroleum degradation, bacterial communities, functional genes and ecological interactions in application of petroleum remediation under thermophilic conditions. [Display omitted] •Consortium HT promoted the removal of medium, long-chain alkanes at high temperature.•Exogenous HT consortium thrived in high temperature petroleum-contaminated soil.•Genes related to n-alkanes degradation and thermotolerance were up-regulated.•Bioaugmentation with HT led to a more tightly regulated, complex, and stable network.