Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
Bioelectrochemistry. 2019 Dec;130:107333. doi: 10.1016/j.bioelechem.2019.107333. Epub 2019 Jul 18.
Electro-fermentation (EF) is an emerging and promising technology consisting in the use of a polarized electrode to control the spectrum of products deriving from anaerobic bioprocesses. Here, the effect of electrode polarization on the fermentation of glucose has been studied with two mixed microbial cultures, both in the absence and in the presence of exogenous redox mediators, to verify the viability of the proposed approach under a broader and previously unexplored range of operating conditions. In unmediated experiments, EF (with the cathode polarized at -700 mV vs. SHE, Standard Hydrogen Electrode) caused an increase in the yield of butyric acid production provided that glucose was consumed along with its own fermentation products (i.e. acetic acid and ethanol). The maximum obtained yield accounted for 0.60 mol mol. Mediated experiments were performed with Neutral Red or AQDS at a concentration of 500 μM both in the absence and in the presence of the electrode polarized at -700 mV or -300 mV vs. SHE, respectively. Mediators showed a high selectivity towards the generation of n-butyric acid isomer from the condensation of acetate and ethanol, hence suggesting that they provided microbial cells with the required reducing power otherwise deriving from glucose in unmediated experiments.
电发酵（EF）是一种新兴且有前途的技术，它利用极化电极来控制厌氧生物过程产生的产品谱。在这里，研究了电极极化对葡萄糖发酵的影响，使用了两种混合微生物培养物，在没有和有外源氧化还原介体的情况下，以验证在更广泛和以前未探索的操作条件范围内提出的方法的可行性。在未经调解的实验中，EF（将阴极在相对于 SHE 的-700 mV 处极化）导致丁酸产量的增加，前提是葡萄糖与自身发酵产物（即乙酸和乙醇）一起消耗。获得的最大产率为 0.60 mol/mol。在不存在和存在分别相对于 SHE 极化至-700 mV 或-300 mV 的电极的情况下，以 500 μM 的浓度进行了中性红或 AQDS 的介导实验。介体对乙酸和乙醇缩合生成正丁酸异构体表现出很高的选择性，因此表明它们为微生物细胞提供了所需的还原力，否则在未经调解的实验中这种还原力来自葡萄糖。
