Nutrient depletion is the main limiting factor in the crude oil bioaugmentation process.

The biodegradation was considered as the prime mechanism of crude oil degradation. To validate the efficacy and survival of the crude oil-degrading strain in a bioremediation process, the enhanced green fluorescent protein gene (egfp) was introduced into Acinetobacter sp. HC8-3S. In this study, an oil-contaminated sediment microcosm was conducted to investigate the temporal dynamics of the physicochemical characterization and microbial community in response to bacterium amendment. The introduced strains were able to survive, flourish and degrade crude oil quickly in the early stage of the bioremediation. However, the high abundance cannot be maintained due to the ammonium (NH4+-N) and phosphorus (PO43--P) contents decreased rapidly after 15 days of remediation. The sediment microbial community changed considerably and reached relatively stable after nutrient depletion. Therefore, the addition of crude oil and degrading cells did not show a long-time impact on the original microbial communities, and sufficient nitrogen and phosphorus nutrients ensures the survive and activity of degrader. Our studies expand the understanding of the crude oil degradative processes, which will help to develop more rational bioremediation strategies.