Corrosion inhibition of stainless steel due to a sulfate-reducing bacteria （SRB） biofilm in seawater was studied. By atomic force microscopy, a layer of fish-scale-like biofilm was found to form as stainless steel c...Corrosion inhibition of stainless steel due to a sulfate-reducing bacteria （SRB） biofilm in seawater was studied. By atomic force microscopy, a layer of fish-scale-like biofilm was found to form as stainless steel coupons were exposed to the culture media with SRB, and this biofilm grew more and more compact. As a result, coupons＇ surface under the biofilm turned irregular less slowly than that exposed to the sterilized culture media. Then, physicoelectric characteristics of the electrode/biofilrn/solution interface were investigated by electro- chemical impedance spectroscopy （EIS）, and the coverage of the biofilm as well as the relative irregularity of coupons＇ surface was also re- corded by EIS spectra.. Finally, anodic cyclic polarization results further demonstrated the protective property of the biofilm. Therefore, in es- timation of SRB-implicated corrosion of stainless steel, not only the detrimental SRB metabolites but also the protective SRB biofilm as well should be taken into account.展开更多
Microbial electrosynthesis(MES)employs microbial catalysts and electrochemistry to enhance CO_(2)bioconversion to organics with concurrent waste biorefining capability.The aim of this review is to comprehensively disc...Microbial electrosynthesis(MES)employs microbial catalysts and electrochemistry to enhance CO_(2)bioconversion to organics with concurrent waste biorefining capability.The aim of this review is to comprehensively discuss the current state of the art and prospects of medium chain fatty acids(MCFAs)production in MES from CO_(2)and organic wastes.Fundamental mechanisms and development of MCFAs production via conventional fermentation are introduced as well.Studies on MCFAs production in MES are summarized,highlighting the strategy of multiple-electron donors(EDs).Challenges for MCFAs production in MES from CO_(2)are presented,and the primary discussions included methanogenesis inhibition,adenosine triphosphate(ATP)limitations of acetogens,and production of limited EDs via solventogenesis.Possible applications of electrochemical approaches to promote the bioconversion of actual waste materials with MCFAs production are analyzed.Finally,future directions are explored,including multi-stage reactions,substrate supply,product extraction,and microbial pathways.展开更多
为了研究天然赤铁矿对微生物胞外电子传递机制,以长沙和海口红壤为例,构建了双室反应体系对红壤微生物与天然赤铁矿间氧化还原作用及胞外电子传递过程进行表征。研究显示,增加赤铁矿作为电子受体后,长沙与海口红壤体系开路电压由425.28...为了研究天然赤铁矿对微生物胞外电子传递机制,以长沙和海口红壤为例,构建了双室反应体系对红壤微生物与天然赤铁矿间氧化还原作用及胞外电子传递过程进行表征。研究显示,增加赤铁矿作为电子受体后,长沙与海口红壤体系开路电压由425.28、414.64 m V提升至511.46、532.52 m V,最大输出功率由221.5、171.0 m W/m^3提升至431.4、260.2 m W/m^3。电化学循环伏安测试显示在0.43、0.55 V(相对于饱和甘汞电极;vs.SCE)处出现Fe(Ⅲ)还原峰及Fe(Ⅱ)氧化峰,指证新氧化还原反应的引入。电化学阻抗谱(EIS)拟合结果显示赤铁矿电极极化内阻R_p自44840Ω降至665Ω,从动力学层面表明电极反应导致的电势降低有利于电子转移。实验研究结果表明,红壤环境中以赤铁矿为代表的铁氧化物能够有效参与并促进微生物胞外电子传递。展开更多
Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrr...Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.展开更多
基金supported by the projects of Qujing Normal University (Nos.TD200901 and 2009ZD009)
文摘Corrosion inhibition of stainless steel due to a sulfate-reducing bacteria （SRB） biofilm in seawater was studied. By atomic force microscopy, a layer of fish-scale-like biofilm was found to form as stainless steel coupons were exposed to the culture media with SRB, and this biofilm grew more and more compact. As a result, coupons＇ surface under the biofilm turned irregular less slowly than that exposed to the sterilized culture media. Then, physicoelectric characteristics of the electrode/biofilrn/solution interface were investigated by electro- chemical impedance spectroscopy （EIS）, and the coverage of the biofilm as well as the relative irregularity of coupons＇ surface was also re- corded by EIS spectra.. Finally, anodic cyclic polarization results further demonstrated the protective property of the biofilm. Therefore, in es- timation of SRB-implicated corrosion of stainless steel, not only the detrimental SRB metabolites but also the protective SRB biofilm as well should be taken into account.
基金supported by the National Natural Science Foundation of China(51908131)Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(19K05ESPCT)+1 种基金the Chinese Academy of Sciences(CAS)Key Laboratory of Environmental and Applied Microbiology&Environmental Microbiology Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences(KLCAS-2019-1)the Fujian Provincial Natural Science Foundation of China(2020J01563)。
文摘Microbial electrosynthesis(MES)employs microbial catalysts and electrochemistry to enhance CO_(2)bioconversion to organics with concurrent waste biorefining capability.The aim of this review is to comprehensively discuss the current state of the art and prospects of medium chain fatty acids(MCFAs)production in MES from CO_(2)and organic wastes.Fundamental mechanisms and development of MCFAs production via conventional fermentation are introduced as well.Studies on MCFAs production in MES are summarized,highlighting the strategy of multiple-electron donors(EDs).Challenges for MCFAs production in MES from CO_(2)are presented,and the primary discussions included methanogenesis inhibition,adenosine triphosphate(ATP)limitations of acetogens,and production of limited EDs via solventogenesis.Possible applications of electrochemical approaches to promote the bioconversion of actual waste materials with MCFAs production are analyzed.Finally,future directions are explored,including multi-stage reactions,substrate supply,product extraction,and microbial pathways.
文摘为了研究天然赤铁矿对微生物胞外电子传递机制,以长沙和海口红壤为例,构建了双室反应体系对红壤微生物与天然赤铁矿间氧化还原作用及胞外电子传递过程进行表征。研究显示,增加赤铁矿作为电子受体后,长沙与海口红壤体系开路电压由425.28、414.64 m V提升至511.46、532.52 m V,最大输出功率由221.5、171.0 m W/m^3提升至431.4、260.2 m W/m^3。电化学循环伏安测试显示在0.43、0.55 V(相对于饱和甘汞电极;vs.SCE)处出现Fe(Ⅲ)还原峰及Fe(Ⅱ)氧化峰,指证新氧化还原反应的引入。电化学阻抗谱(EIS)拟合结果显示赤铁矿电极极化内阻R_p自44840Ω降至665Ω,从动力学层面表明电极反应导致的电势降低有利于电子转移。实验研究结果表明,红壤环境中以赤铁矿为代表的铁氧化物能够有效参与并促进微生物胞外电子传递。
基金Project(2010CB630903) supported by the National Basic Research Program of ChinaProject(51374249) supported by the National Natural Science Foundation of China
文摘Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.
