Enhancement of Microbial and Metabolic Mechanisms in an Aerobic Bioreactor with Immobilized Microflora by Simple and Complex Electron Donors

Microflora immobilization is promising for nutrient removal applications in sewage; however, the metabolic and microbial mechanism needs to be further explored. Heterotrophic nitrification-aerobic denitrification (HN-AD) bacterium efficient nitrogen (N) bacteria were selected immobilized on corncob particles using alginate polymer prepare microbe–organic complex beads. The beads then added into activated sludge under a continuous-flow aerobic bioreactor with sufficient sodium acetate also applied as simple electron donor. role of donors carbon-rich conditions was studied. Results showed that total rate improved by 8.3% (reaching 91.2%) ammonium rates approximately 98%. Only 0.59 mg/L nitrate detected treatment group. 16S rRNA gene sequencing results bacterial richness within group significantly higher than control (p < 0.05), KEGG pathways analysis indicated carbon (C) metabolism N-cycle-related genes improved. This suggested generated C sources nourished diverse species related N cycles so could strengthened microflora.