title: Universally improving effect of mixed electron donors on the CO₂ fixing efficiency of non-photosynthetic microbial communities from marine environments.
abstract: The universality of improved CO₂ fixing upon the addition of mixed electron donors (MEDs) composed of Na₂S, NO₂(-), and S₂O₃(2-) to non-photosynthetic microbial communities (NPMCs) obtained from 12 locations in four oceans of the world was validated. The CO₂ fixing efficiencies of NPMCs were universally enhanced by MED compared with those obtained using H₂ alone as electron donor, with average increase of about 276%. An increase in microbial inoculation concentration could increase the net amount of CO₂ fixing to 853.34 mg/L in the presence of MED. NO₂(-) and S₂O₃(2-) may play the roles of both electron acceptor and electron donor under aerobic conditions, which may improve the energy utilization efficiency of NPMC and enhance the CO₂ fixation efficiency. The sequence determination of 16S ribosomal deoxyribonucleic acid (rDNA) from 150 bacteria of NPMC showed that more than 50% of the bacteria were symbiotic and there were many heterotrophic bacteria such as Vibrio natriegens. These results indicate that NPMC acts as a symbiotic CO₂ fixing system. The interaction between autotrophic and heterotrophic bacteria may be a crucial factor supporting ladder utilization and recycling of energy/carbon source.
authors.affiliation: School of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China. Electronic address: hujj0101@gmail.com.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Hu
authors.affiliation: School of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China. Electronic address: celwang@tongji.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Low-Carbon Conversion Science and Engineering Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
authors.forename: Shiping
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
authors.forename: Yuanqing
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Fangming
authors.initials: F
authors.lastname: Jin
authors.affiliation: School of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Fu
authors.affiliation: Polar Research Institute of China, Shanghai 200136, China.
authors.forename: Huirong
authors.initials: H
authors.lastname: Li
mesh_terms: D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000378:metabolism*; D009792:Oceans and Seas; D012623:Seawater; D014871:Water Microbiology
chemical_list: D002245:Carbon Dioxide
keywords: CO(2) fixing; Heterotrophic bacteria; Mixed electron donors; Non-photosynthetic microbial community; Symbiotic bacteria