在Thermincola ferriacetica的阳极生物膜中的pH依赖性表明了以质子为依赖的电化学反应
Bradley G Lusk1,2, Isaias Peraza1, Gaurav Albal1
1Swette Center for Environmental Biotechnology , The Biodesign Institute at Arizona State University , P.O. Box 875701, Tempe , Arizona 85287 , United States.
Journal of the American Chemical Society
|April 14, 2018
概括
这项研究显示pH是阳极呼吸细菌 (ARB) 主要限制能量的因素. 铁菌生物膜显示质子依赖的电子转移,这表明pH梯度在热力学上限制了ARB呼吸.
科学领域:
- 微生物学
- 电化学
- 生物能源
背景情况:
- 阳极呼吸细菌 (ARB) 对于了解微生物代谢和细胞外电子转移 (EET) 是至关重要的.
- 监测ARB的电化学反应揭示了它们的呼吸过程中的速度限制.
- 生物化学过程与电子的交互是ARB功能的关键.
研究的目的:
- 在Thermincola ferriacetica阳极生物膜中研究质子依赖的电子转移反应.
- 确定pH,电子供体 (乙酸盐) 和生物膜生长对电化学潜力的影响.
- 了解pH梯度对ARB呼吸施加的热力学限制.
主要方法:
- 在60°C的温度下研究了热友性GRAM阳性ARB,Thermincola ferriacetica.
- 不同的pH值,酸盐的存在,生物膜生长条件.
- 在非转换条件下测量了电化学中点电位 (EKA) 和正规氧化还原电位 (E°).
主要成果:
- 确定pH值是影响T. ferriacetica阳极生物膜能量的主要因素.
- 在E°'中观察到48±7mV/pH单位转移,这表明依赖质子的速度限制过程.
- 结果表明ARB在热力学上受到pH梯度的限制,尤其是在低可用的能量 (<200mV) 的情况下.
结论:
- 质子传输限制和pH梯度对ARB能量有显著影响.
- 被pH影响的观察到的Nernstian行为表明与质子转位膜蛋白的联系.
- EKA和E°'取决于pH值;建议在特定的批量pH值下报告这些值.
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