不同阳极电势驯化对于Clostridium butyricum 葡萄糖代谢影响研究

The Glucose Metabolism Variation of Clostridium butyricum during Domestication with Different Anode Potentials

摘要:

新筛选出的Clostridium butyricum 作为研究菌株，研究其在不同阳极电势驯化期内葡萄糖代谢与电化学活性的差异。使用1mM葡萄糖为底物连接1000 Ω外电阻时，电池的输出电压约为0.09 V。该电池性能显示出C.butyricum 具有良好的电活性。在控制阳极电势（＋0.6, ＋0.2 和 －0.2 V，vs Ag/AgCl）驯化菌株的过程中，C.butyricum电活性及其葡萄糖代谢显示出明显的不同。在驯化后期，0.6 V和0.2 V组的最大输出电流分别为1.8和1.2 mA，而-0.2 V组只有0.02 mA。但是表征游离菌体的OD600的结果显示-0.2 V组具有大量游离菌体。这意味着高阳极电势驯化出的生物膜具有高电活性。不同组别在驯化末期葡萄糖代谢也出现了不同。乳酸，丁二酸和乙醇的含量随着生物膜电活性的增高而减少，同时乙酸和丁酸的含量却上升。但是-0.2 V组生成了大量丁酸（345 mg/L），同时却只有少量二氧化碳生成（4 %）。实验结果表明高阳极电势促进生物膜的电极呼吸代谢同时抑制其发酵代谢从而表现出高生物电活性。本文拓展了电活性微生物在发酵条件下产电过程的理解。

Abstract:

Clostridium butyricum was used as a type strain for studying its glucose metabolism and bioelectrical activity with different anode potentials (+0.6, +0.2 and -0.2 V, vs Ag/AgCl). When using 1 mM glucose as substrate and connecting 1000 Ωresistance, the output voltage of the microbial fuel cell was about 0.09 V, which proved a good bioelectrical activity of the strain. During the domestication of the strain with three anode potentials, the bioelectrical activities and glucose metabolisms of the three groups were quite different. The maximum output current of group 0.6 and 0.2 V were ca. 1.8 and 1.2 mA, while the group -0.2 was only ca. 0.02 mA at the end of domestication. While the OD600 of group -0.2 was 0.3 which was much higher than the other two groups (ca. 0.01). The end products of glucose metabolism in different groups and domestication cycles were different. At the beginning of the domestication, the end productions were similar. Succinate, lactate, ethanol, acetate and hydrogen were the main end productions, which suggested the metabolism type of three groups was fermentation. At the end of domestication, the content of succinate, lactate, ethanol and hydrogen of group 0.6 and 0.2 were decreased, carbon dioxide increased. While a large sum of butyrate generated in group-0.2. In addition, the content of carbon dioxide in this group was much less than group0.6 and 0.2. The glucose metabolism analysis showed a transformation of metabolism from fermentation to anode-respiration with the increasement of the strain C. butyricum bioelectrical activity. The results provided a new perception into the influence of anode potential on the bioelectrochemical systems.