Main components of free organic carbon generated by obligate chemoautotrophic bacteria that inhibit their CO2 fixation

Saiwei Zhang; Xiaohua Fu; Yonglei Han; Liwen Wei; Mengnan Liu; Ya-Nan Wang; Lei Wang

doi:10.1016/j.isci.2022.105553

Main components of free organic carbon generated by obligate chemoautotrophic bacteria that inhibit their CO₂ fixation

iScience. 2022 Nov 11;25(12):105553. doi: 10.1016/j.isci.2022.105553. eCollection 2022 Dec 22.

Authors

Saiwei Zhang^{1

2}, Xiaohua Fu^{1

2}, Yonglei Han^{1

2}, Liwen Wei^{1

2}, Mengnan Liu^{1

2}, Ya-Nan Wang³, Lei Wang^{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, China.
³ Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China.

Abstract

Chemoautotrophic bacteria play an important role in combating the rise in global CO₂. However, recently it was found that extracellular free organic carbon (EFOC) generated by chemoautotrophic bacteria inhibits their CO₂ fixation. Although continuous-flow membrane bioreactor can remove EFOC and enrich bacteria, it may also remove beneficial bio-factors for bacterial growth. Finding out the main inhibitory factors and inhibitory mechanisms in EFOC can provide theoretical guidance for the development of targeted inhibitory component removal technology. The results show a significant negative correlation between the increasing proportion of small-molecule EFOC and the decreasing trend of CO₂ fixation efficiency, and simulation experiments confirm that the small molecule organics such as amino acids and organic acids are the main components of EFOC that inhibit CO₂ fixation by inhibiting ribulose bisphosphate carboxylase/oxygenase (RuBisCO) gene (cbb) transcription efficiency. Therefore, amino acids and organic acids are suggested to be recovered to promote efficient CO₂ fixation of autotrophic bacteria.

Keywords: Biochemistry; biophysics; microbiology.