Bacterial succession and co-occurrence patterns of an enriched marine microbial community during light crude oil degradation in a batch reactor.

The aim of this study was to investigate the dynamic changes in the bacterial structure and potential interactions of an acclimatized marine microbial community during a light crude oil degradation experiment. The bacterial community effectively removed 76·49% of total petroleum hydrocarbons after 30 days, as evidenced by GC-FID and GC-MS analyses. Short-chain alkanes and specific aromatic compounds were completely degraded within the first 6 days. High-throughput sequencing of 16S rRNA gene indicated that the starting bacterial community was mainly composed by Marinobacter and more than 30 non-dominant genera. Bacterial succession was dependent on the hydrocarbon uptake with Alcanivorax becoming dominant during the highest degradation period. Sparse correlations for compositional data algorithm revealed one operational taxonomic unit (OTU) of Muricauda and an assembly of six OTUs of Alcanivorax dieselolei and Alcanivorax hongdengensis as critical keystone components for the consortium network maintenance and stability. This work exhibits a stabilized marine bacterial consortium with the capability to efficiently degrade light crude oil in 6 days, under laboratory conditions. Successional and interaction patterns were observed in response to hydrocarbon consumption, highlighting potential interactions between Alcanivorax and keystone non-dominant OTUs over time. Our results contribute to the understanding of interactions and potential roles of specific members of hydrocarbonoclastic marine bacterial communities, which will be useful for further bioaugmentation studies concerning the associations between indigenous and introduced micro-organisms.