Identification of novel strain Acinetobacter baumannii H1 and its improvement capacity for nutrient removal after coimmobilized on activated carbon and CaCO3 in real aquaculture wastewater

Abstract

A new strain H1, Acinetobacter baumannii, exhibited the 96 % nitrogen and 76 % phosphate removal efficiencies in suspension environment after 48 h, and the optimal conditions were obtained at pH of 7–8, temperature of 30 °C, carbon source of succinate, carbon-nitrogen ratio of 10 and phosphorus-nitrogen ratio of 0.2, respectively. The immobilization experiments with activated carbon and CaCO₃ were carried out, the optimal formula was 30 g/L CaCO₃, 15 g/L activated carbon-bacteria complex, 2 % CaCl₂ and a 1:1 embedding agent ratio. The removal efficiency of NH₄⁺-N, total nitrogen, total phosphorus and chemical oxygen demand in immobilized H1 was 288.89 %, 121.87 %, 135.69 % and 667.21 % higher than that by free strain in group With Indigenous Bacteria, respectively. Under the real water environment, the nitrogen concentrations in the immobilization groups were 3–4 times lower than those of the suspension groups, and the abundances of N and P metabolism-associated bacterial communities (Proteobacteria and Patescibacteria) were higher in the immobilization groups. These results provided an approach for the practical application in aquaculture tailwater treatment.