title: Optimization of inorganic carbon sources to improve the carbon fixation efficiency of the non-photosynthetic microbial community with different electron donors.
abstract: As the non-photosynthetic microbial community (NPMC) isolated from seawaters utilized inorganic carbon sources for carbon fixation, the concentrations and ratios of Na2CO3, NaHCO3, and CO2 were optimized by response surface methodology design. With H2 as the electron donor, the optimal carbon sources were 270 mg/L Na2CO3, 580 mg/L NaHCO3, and 120 mg/L CO2. The carbon fixation efficiency in response to total organic carbon (TOC) was up to 30.59 mg/L with optimal carbon sources, which was about 50% higher than that obtained with CO2 as the sole carbon source. The mixture of inorganic carbon sources developed a buffer system to prevent acidification or alkalization of the medium caused by CO2 or Na2CO3, respectively. Furthermore, CO2 and HCO3(-), the starting points of carbon fixation in the pathways of Calvin-Benson-Bassham and 3-hydroxypropionate cycles, were provided by the carbon source structure to facilitate carbon fixation by NPMC. However, in the presence of mixed electron donors composed of 1.25% Na2S, 0.50% Na2S2O3, and 0.457% NaNO2, the carbon source structure did not exhibit significant improvement in the carbon fixation efficiency, when compared with that achieved with CO2 as the sole carbon source. The positive effect of mixed electron donors on inorganic carbon fixation was much higher than that of the carbon source structure. Nevertheless, the carbon source structure could be used as an alternative to CO2 when using NPMC to fix carbon in industrial processes.
authors.affiliation: a State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering , Tongji University , Shanghai 200092 , People's Republic of China.
authors.forename: Ya-nan
authors.initials: YN
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Yi-na
authors.initials: YN
authors.lastname: Shan
authors.forename: Jiajun
authors.initials: J
authors.lastname: Hu
authors.forename: Yiufai
authors.initials: Y
authors.lastname: Tsang
authors.forename: Yu
authors.initials: Y
authors.lastname: Hu
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Fu
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Le
mesh_terms: D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000378:metabolism*; D052837:Chemoautotrophic Growth; D006859:Hydrogen / Q000378:metabolism*; D059013:Microbial Consortia; D012977:Sodium Nitrite / Q000378:metabolism; D013440:Sulfides / Q000378:metabolism; D013885:Thiosulfates / Q000378:metabolism
chemical_list: D013440:Sulfides; D013885:Thiosulfates; D002245:Carbon Dioxide; D006859:Hydrogen; C017717:sodium thiosulfate; D012977:Sodium Nitrite; C033479:sodium sulfide
keywords: carbon fixation; electron donor; inorganic carbon sources; non-photosynthetic microbial community (NPMC); response surface methodology design