Performance and Microbial Community Analysis of Integrated Bioremediation Systems with Photosynthetic Bacteria in Treating Mariculture Tailwater

Mariculture tailwater poses significant environmental challenges such as water pollution and eutrophication. Photosynthetic bacteria (PSB) have been widely used for pollutant treatment. The integrated aquaculture wastewater bioremediation system (IAWBS) consists of four key components: sedimentation, biofilm, shellfish, and macro-algae. However, there is still some room for improvement in the treatment efficiency of the IAWBS. In this study, PSB (Rhodopseudomonos, Rhodobacteria, Rhodococcus) were added to the system. High-throughput amplicon of 16S rRNA, PERMANOVA, NMDS and other statistical analyses were used to investigate the impacts of PSB. The results showed that significant removal efficiencies of COD_Mn, NH₄⁺-N, NO₃⁻-N, NO₂⁻-N, PO₄³⁻-P were 71.42%, 91.37%, 91.72%, 87.20%, and 88.80%, respectively. The impact of PSB on bacterioplankton community (BC) was not affected by the time interval but affected by different units, Proteobacteria, Bacteriodia and Actinobacteria were the most abundant phyla in all the units. Alpha diversity underscored a significant decrease in bacterial community diversity due to the PSB. Notably, the PERMANOVA analysis highlighted a significant interaction between the time interval and treated unit, influencing the composition of the microbial community (R² = 0.152; P = 0.001). This study provides a better understanding of the role of photosynthetic bacteria in an integrated bioremediation system that can effectively treat mariculture tailwater, which is of great significance for the sustainable development of aquaculture.