Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Bioelectrochemistry. 2017 Oct;117:23-28. doi: 10.1016/j.bioelechem.2017.05.001. Epub 2017 May 13.
Microbial electrosynthesis (MES) is a promising technique that converts electricity and CO to biofuels using microbes as the catalysts. However, most of previous MES are conducted at mesophilic temperatures and challenged by low performances. Here we report a significant electrosynthesis performance enhancement via immobilization of a thermophilic microbe to cathodes. A temperature-dependent electron uptake rate of Moorella thermoautotrophica was observed at a cathode potential of -0.4V (vs. SHE), with a maximum current density of 63.47mAm at 55°C. Moreover, electrosynthesis rates of formate and acetate at 55°C were accelerated by 23.2 and 2.8 fold than those of 25°C, respectively. Compared with natural biofilms, immobilization of M. thermoautotrophica with carbon nanoparticles to electrodes further enhanced acetate and formate production rates (by 14 and 7.9 fold), reaching 58.2 and 63.2mmolmday at a coulombic efficiency of 65%, respectively. To our best knowledge, these are the highest electrosynthesis rates obtained thus far for pure cultures under the conditions of -0.4V (vs. SHE) and 55°C. This study, for the first time, demonstrates that embedding microbes to electrodes by carbon nanoparticles is a facile and efficient method of improving MES performance.
微生物电合成（MES）是一种很有前途的技术，它利用微生物作为催化剂，将电能和 CO 转化为生物燃料。然而，大多数先前的 MES 都是在中温条件下进行的，并且受到性能低下的挑战。在这里，我们通过将嗜热微生物固定在阴极上来显著提高电合成性能。在 -0.4V（相对于 SHE）的阴极电位下，观察到嗜热微生物 Moorella thermoautotrophica 的电子摄取率随温度而变化，在 55°C 时最大电流密度为 63.47mAm。此外，在 55°C 时，甲酸和乙酸的电合成速率分别比在 25°C 时提高了 23.2 倍和 2.8 倍。与天然生物膜相比，用碳纳米粒子将 M. thermoautotrophica 固定在电极上进一步提高了乙酸和甲酸的产率（分别提高了 14 倍和 7.9 倍），在库仑效率为 65%时，达到了 58.2 和 63.2mmolmday。据我们所知，这是迄今为止在 -0.4V（相对于 SHE）和 55°C 条件下，纯培养物获得的最高电合成速率。本研究首次证明，通过碳纳米粒子将微生物嵌入电极是一种提高 MES 性能的简单而有效的方法。
