Coupled Carbon, Mn(II), and Nitrogen Cycles in a Mixotrophic Biofilm Reactor and Microbial Community Structure

Abstract A novel mixotrophic biofilm reactor (MBR) was operated to simultaneously remove total organic carbon, nitrate, and Mn(II). Effects of some key factors on mixotrophic denitrification were investigated in lab‐scale bioreactors. Optimized conditions obtained from the MBR were used to validate the experiments, proving their feasibility. High‐throughput sequencing was employed to analyze the microbial communities of the MBR. The community diversity in the MBR was markedly influenced by the ratio of C inorganic :C organic . The species were increased with lower C inorganic :C organic concentration. Pseudomonas was detected as the dominant species in the MBR, indicating that Pseudomonas sp. SZF15 and Pseudomonas sp. H‐117 play a primary role in the process of nitrate removal.