A synthetic Glutamicibacter consortium efficiently removes ammonium and nitrite from aquaculture wastewater

Accumulation of inorganic nitrogen in aquaculture water exerts toxic effects on aquatic animals. This study is the first to report the use of a synthetic Glutamicibacter consortium for nitrogen removal from aquaculture wastewater. Two high efficiency heterotrophic nitrification-aerobic denitrification strains were isolated from cattle manure and aquaculture sediments and identified as G. arilaitensis NFB2-4 and G. nicotianae CYN-C5. A synthetic consortium S11, composed of these two strains, exhibited marked synergistic nitrogen removal: at pH 6-9 and C/N ≥ 15, it removed 95 % of NH₄⁺-N and 97 % of NO₂^--N (initial concentration 30 mg L^-1 each) within 24 h, with degradation rates of 0.95 mg-N L^-1h^-1 and 1.06 mg-N L^-1h^-1, respectively. This represents a 15 %-25 % improvement over single-strain cultures. Hemolysis assays confirmed biosafety with a hemolytic rate below 2 %. After immobilizing the consortium on hydrophilic sponges, 76 % of NH₄⁺-N and 96 % of NO₂^--N were removed at a hydraulic retention time of only 20 min in a recirculating system. In an industrial-scale recirculating aquaculture trial, the consortium reduced NO₂^--N to a residual level of 23.91 % after 24 d, or 24.31 % after 90 d, outperforming commercial products by more than 40 %, demonstrating strong potential for commercialization. This work provides an efficient, stable, and eco-friendly microbial solution for treating aquaculture wastewater.