Bioaugmentation‐Driven Bioremediation: Microbial Community Dynamics and Hydrocarbon Degradation Efficiency in Marine Sediments

Abstract

Bioaugmentation is effective for remediating petroleum‐contaminated seawater, but its application in marine sediments remains underexplored. This study investigated the enhancing effects and mechanisms of bioaugmentation on total petroleum hydrocarbons (TPHs) degradation in marine sediments over 60 days. The bioaugmentation (B) group achieved a TPH degradation rate 1.89 times higher than the natural restoration (N) group. GC‐MS analysis revealed significantly lower residual C 13 –C 22 hydrocarbon concentrations in Group B. Excitation–emission matrix spectroscopy showed elevated soluble microbial by‐products and tyrosine‐like substances in Group B, whereas tryptophan‐like substances accumulated in Group N. Despite an initial decline following inoculation, microbial diversity indices (Chao1 and Shannon) in Group B increased progressively over time, eventually exceeding those of Group N by Day 60, indicating dynamic community restructuring. Bacillus dominated the initial stage of bioaugmentation, while Sporolactobacillus became dominant after 60 days, both of which were reported as potential petroleum degraders. Metagenomic analysis indicated that key genes involved in petroleum hydrocarbon degradation were substantially enriched in Group B throughout the remediation period, reflecting enhanced genetic potential. Molecular docking simulations suggested that alkylsuccinate synthase (assA) enzymes in petroleum‐degrading bacteria might facilitate hydrocarbon binding through hydrogen bonds and hydrophobic interactions, which could potentially contribute to enhanced degradation. These in silico findings provided predictive structural insights into potential degradation mechanisms and required experimental validation. This study contributed to elucidating the degradation efficacy and potential mechanistic enhancements of bioaugmentation, highlighting its viability for the bioremediation of TPHs‐contaminated marine sediments.