Enhanced wastewater treatment using microalgae-bacteria-fungi consortia with brassinolide

This study assessed microalgae monocultures/consortia with brassinolide (BR) for aquaculture wastewater treatment; co-cultures of Scenedesmus obliquus, Bacillus subtilis, Phanerochaete chrysosporium showed superior pollutants removal efficiencies. In medium-concentration wastewater, on Day 7, 91 % removal efficiency was achieved for chemical oxygen demand (COD), 94 % for total nitrogen (TN), 92 % for total phosphorus (TP), 94 % for Zn²⁺, 96 % for Cu²⁺, and over 99 % for tetracycline (TC). The three-culture system outperformed the microalgae monoculture control, with the latter reaching only 82 % COD, 85 % TN, 83 % TP, 67 % Zn²⁺, 63 % Cu²⁺, and 87 % TC removal efficiency under the same conditions. Further, adding 6 mg L^-1 BR significantly improved (P < 0.05) the removal efficiency to 94 % COD, 96 % TN, and 94 % TP on Day 7. These findings provided a sustainable strategy integrating multi-species consortia with BR to boost aquaculture wastewater treatment efficiency.