Evaluation of response of dynamics change in bioaugmentation process in diesel-polluted seawater via high-throughput sequencing: Degradation characteristic, community structure, functional genes

[Display omitted] •Hydrogen bonded between diesel and bacteria are by molecular simulation analysis.•Community diversity has recovered tendency during the process of bioaugmentation.•Add diesel and bioaugmentation has bigger influence on bacteria community than sites.•The abundance of functional genes about oil degradation and metabolism increased.•Degradation rate of diesel by bioaugmentation on polluted-seawater was high than 70 %. Identification of microorganisms that contribute to the whole microbial community is important. In this study, dynamic changes in bioaugmentation process in diesel-polluted seawater collected from two different sites were assessed via simulation experiments. Ultraviolet spectrophotometry and analysis using the molecular operating environment software revealed that the degradation rate of diesel due to bioaugmentation was higher than 70 % after 45 days because of the formation of hydrogen bonds among biosurfactants and diesel components. Community structure and functional genes were analysed via high-throughput sequencing. Results showed that community diversity recovered during bioaugmentation. Principal coordinate analysis showed that the difference in microbial community between the two sites was considerably smaller than that when diesel was added and bioaugmentation was conducted. After bioaugmentation, the main families playing key roles in degradation that became dominant were Alcanivoracaceae, Rhodobiaceae, and Rhodospirillaceae. Moreover, the abundance of functional genes remarkably increased at two different sites.