title: Magnesium ions improving the growth and organics reduction of Rhodospirillum rubrum cultivated in sewage through regulating energy metabolism pathways.
abstract: Rhodospirillum rubrum has the potential for biomass resource recycling combined with sewage purification. However, low biomass production and yield restricts the potential for sewage purification. This research investigated the improvement of biomass production, yield and organics reduction by Mg²⁺ in R. rubrum wastewater treatment. Results showed that with optimal dosage (120 mg/L), biomass production reached 4,000 mg/L, which was 1.5 times of that of the control group. Biomass yield was improved by 43.3%. Chemical oxygen demand (COD) removal reached over 90%. Hydraulic retention time was shortened by 25%. Mechanism analysis indicated that Mg²⁺ enhanced the isocitrate dehydrogenase and Ca²⁺/Mg²⁺-ATPase activities, bacteriochlorophyll content on respiration and photophosphorylation. These effects then enhanced ATP production, which led to more biomass accumulation and COD removal. With 120 mg/L Mg²⁺ dosage, the isocitrate dehydrogenase and Ca²⁺/Mg²⁺-ATPase activities, bacteriochlorophyll content, ATP production were improved, respectively, by 33.3%, 50%, 67%, 41.3% compared to those of the control group.
authors.affiliation: Center of Research on Life Science and Environmental Science, Harbin University of Commerce, Harbin, 150075, China.
authors.forename: Chang-Ru
authors.initials: CR
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China E-mail: woacademic@163.com.
authors.forename: Pan
authors.initials: P
authors.lastname: Wu
authors.affiliation: Center of Research on Life Science and Environmental Science, Harbin University of Commerce, Harbin, 150075, China.
authors.forename: Lang
authors.initials: L
authors.lastname: Lang
authors.affiliation: Center of Research on Life Science and Environmental Science, Harbin University of Commerce, Harbin, 150075, China.
authors.forename: Ri-Jia
authors.initials: RJ
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China E-mail: woacademic@163.com.
authors.forename: Jian-Zheng
authors.initials: JZ
authors.lastname: Li
authors.affiliation: Center of Research on Life Science and Environmental Science, Harbin University of Commerce, Harbin, 150075, China.
authors.forename: Yu-Bin
authors.initials: YB
authors.lastname: Ji
mesh_terms: D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors; D004734:Energy Metabolism; D008274:Magnesium; D010101:Oxygen Consumption; D059027:Recycling; D012247:Rhodospirillum rubrum / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D012722:Sewage; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D008274:Magnesium; D012722:Sewage; D062065:Wastewater