Synergistic Inorganic Carbon and Denitrification Genes Contributed to Nitrite Accumulation in a Hydrogen-Based Membrane Biofilm Reactor

Si Pang; Bruce E Rittmann; Chengyang Wu; Lin Yang; Jingzhou Zhou; Siqing Xia

doi:10.3390/bioengineering9050222

Synergistic Inorganic Carbon and Denitrification Genes Contributed to Nitrite Accumulation in a Hydrogen-Based Membrane Biofilm Reactor

Bioengineering (Basel). 2022 May 20;9(5):222. doi: 10.3390/bioengineering9050222.

Authors

Si Pang^{1

2}, Bruce E Rittmann³, Chengyang Wu^{1

2}, Lin Yang^{1

2}, Jingzhou Zhou^{1

2}, Siqing Xia^{1

2}

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
² Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
³ Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287, USA.

Abstract

Partial denitrification, the termination of NO₃^--N reduction at nitrite (NO₂^--N), has received growing interest for treating wastewaters with high ammonium concentrations, because it can be coupled to anammox for total-nitrogen removal. NO₂^- accumulation in the hydrogen (H₂)-based membrane biofilm reactor (MBfR) has rarely been studied, and the mechanisms behind its accumulation have not been defined. This study aimed at achieving the partial denitrification with H₂-based autotrophic reducing bacteria in a MBfR. Results showed that by increasing the NO₃^- loading, increasing the pH, and decreasing the inorganic-carbon concentration, a nitrite transformation rate higher than 68% was achieved. Community analysis indicated that Thauera and Azoarcus became the dominant genera when partial denitrification was occurring. Functional genes abundances proved that partial denitrification to accumulate NO₂^- was correlated to increases of gene for the form I RuBisCo enzyme (cbbL). This study confirmed the feasibility of autotrophic partial denitrification formed in the MBfR, and revealed the inorganic carbon mechanism in MBfR denitrification.

Keywords: autotrophic partial denitrification; denitrification genes; inorganic carbon fixing genes; membrane biofilm reactor; microbial community; nitrite accumulation.

Abstract

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