The aniline solution containing nicotinamide adenine dinucleotide(NAD＋ )was electrolyzed. Polyaniline film with NAD＋ formed on the platinum thin plate. The thickness of the film was controlled by the charge consumed...The aniline solution containing nicotinamide adenine dinucleotide(NAD＋ )was electrolyzed. Polyaniline film with NAD＋ formed on the platinum thin plate. The thickness of the film was controlled by the charge consumed in the electrolysis, which was 0.006 C in this case. This electrode, used as an anode, was immersed in the solution containing aniline.A second film formed on this electrode during the electrolysis. The charge passed during the second electrolysis was 0.016 C. Alcohol dehydrogenase(ADH) was immobilized on the polyaniline film based on the isoelectric point of ADH and the doping principle of conducting polymers. The enzyme electrode has a good bioelectrochemical response to ethanol in the absence of a homogeneous mediator. The optimum pH, apparent Michaelis- Menten constant and optimum temperature of ADH immobilized in polyaniline film are 7.83, 7.5 mmol· dm－ 3, and 30.6 ℃ , respectively.The activation energy of the enzyme- catalyzed reaction is 33.5 kJ· mol－ 1. The response current of the enzyme electrode increases linearly with increasing concentration of ethanol below 2.4 mmol· dm－ 3.This enzyme electrode can be used to determine the concentration of ethanol.展开更多
The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbo...The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbon in anoxic environments, which leads to the production and emission of methane, a potent greenhouse gas in the atmosphere, has drawn great attentions from both scientific and public sectors. New organisms and mechanisms involved in methanogenesis and carbon cycling have been uncovered. Interspecies electron transfer is considered as a crucial step in methanogenesis in anoxic environments.Electron-carrying mediators, like H_2 and formate, are known to play the key role in electron transfer. Recently, it has been found that in addition to the conventional electron transfer via chemical mediators, direct interspecies electron transfer(DIET) can occur. In this Review, we describe the ecology and biogeochemistry of methanogenesis and highlight the effect of microbe-mineral interaction on microbial syntrophy. Recent advances in the study of DIET may pave the way towards a mechanistic understanding of methanogenesis and the influence of microbe-mineral interaction on this process.展开更多
文摘The aniline solution containing nicotinamide adenine dinucleotide(NAD＋ )was electrolyzed. Polyaniline film with NAD＋ formed on the platinum thin plate. The thickness of the film was controlled by the charge consumed in the electrolysis, which was 0.006 C in this case. This electrode, used as an anode, was immersed in the solution containing aniline.A second film formed on this electrode during the electrolysis. The charge passed during the second electrolysis was 0.016 C. Alcohol dehydrogenase(ADH) was immobilized on the polyaniline film based on the isoelectric point of ADH and the doping principle of conducting polymers. The enzyme electrode has a good bioelectrochemical response to ethanol in the absence of a homogeneous mediator. The optimum pH, apparent Michaelis- Menten constant and optimum temperature of ADH immobilized in polyaniline film are 7.83, 7.5 mmol· dm－ 3, and 30.6 ℃ , respectively.The activation energy of the enzyme- catalyzed reaction is 33.5 kJ· mol－ 1. The response current of the enzyme electrode increases linearly with increasing concentration of ethanol below 2.4 mmol· dm－ 3.This enzyme electrode can be used to determine the concentration of ethanol.
基金partly supported by the National Natural Science Foundation of China(41630857)the National Basic Research Program of China(2016YFD0200306)
文摘The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbon in anoxic environments, which leads to the production and emission of methane, a potent greenhouse gas in the atmosphere, has drawn great attentions from both scientific and public sectors. New organisms and mechanisms involved in methanogenesis and carbon cycling have been uncovered. Interspecies electron transfer is considered as a crucial step in methanogenesis in anoxic environments.Electron-carrying mediators, like H_2 and formate, are known to play the key role in electron transfer. Recently, it has been found that in addition to the conventional electron transfer via chemical mediators, direct interspecies electron transfer(DIET) can occur. In this Review, we describe the ecology and biogeochemistry of methanogenesis and highlight the effect of microbe-mineral interaction on microbial syntrophy. Recent advances in the study of DIET may pave the way towards a mechanistic understanding of methanogenesis and the influence of microbe-mineral interaction on this process.
