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Updated: Oct 29, 2026

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Macro-scale oxygen pulsing engineers dynamic microbial niches and endogenous carbon cycling for energy-efficient
Zijing An1, Wen-Jie Ma1, Yongbo Hou1
1Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, MOE), School of Environmental Science and Technology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, PR China.
Abstract:
Low-cost and efficient nitrogen removal from low-C/N high-strength ammonium wastewater remains challenging. Herein, a novel macro-scale oxygen pulsing-driven anaerobic/micro-aerobic/anoxic (MOP-AMA) system was developed to treat low-C/N high-strength ammonium wastewater, achieving TN, NH4+-N, and COD removal efficiencies of 97.0 ± 2.2%, 99.1 ± 1.9%, and 97.5 ± 1.6%, respectively, with a specific aeration energy consumption of 20.0 Wh L-1. Functional gene analysis revealed strong enrichment of denitrification-related genes (1635.79 RPKM), while concurrent enrichment of glycogen degradation genes and gltA indicated coordinated glycogen metabolism and TCA cycle activity supplying reducing power and energy for polyhydroxyalkanoates (PHAs) synthesis. At KEGG Level 3, "Metabolic pathways" was the dominant functional category, accounting for 16.78% of the total RPKM-normalized functional abundance. Metagenome-assembled genomes and metatranscriptomics showed that glycogen-accumulating organisms (GAOs) (Candidatus Contendobacter and Candidatus Competibacter) had the highest transcriptional activity in the anaerobic phase (18.57% and 4.73%), while synergistic interactions among AOB, Candidatus Nitrospira defluvii (NOB), and Candidatus Competibacter denitrificans (GAOs) enabled coupled nitrification and endogenous denitrification. Nitrification genes peaked under micro-aerobic conditions, whereas denitrification genes (narGHI, nirKS, norB, nosZ) were highly expressed in the micro-aerobic (930.81, 864.93, 122.59, 277.11 TPM) and anoxic phases (756.21, 688.40, 142.64, 128.22 TPM). These findings demonstrate that macro-scale oxygen pulsing can temporally steer redox processes and electron partitioning for carbon-efficient nitrogen removal, thereby providing guidance for the treatment of carbon-limited high-strength ammonium wastewater.
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