State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China.
Sci Total Environ. 2021 May 1;767:145011. doi: 10.1016/j.scitotenv.2021.145011. Epub 2021 Jan 28.
Bio-electrochemical system (BES) emerges as a versatile approach to handling environmental problems with the harvest of sustainable energy and value-added chemicals. To enhance the butyric acid production from rice straw, microbial fuel cell (MFC) and cathodic electro-fermentation (CEF) systems were constructed in this study. Inoculated with the same mixed culture, fermentative butyric acid production efficiency of the two BESs were evaluated with/without neutral red (NR) as electron mediator, respectively. It was found that the butyric acid fermentation efficiency in the MFC system was inefficient. While, the CEF system presented an evident positive effect on butyric acid production. The production and specific yield of butyric acid in the CEF system reached 5.54 g/L and 0.41 g/g, higher than that in the open circuit (OC) system by 17.37% and 28.13%, respectively. Mass percentage of butyric acid in the produced total volatile fatty acids (VFAs) was also increased from 44.74% to 52.76%. The addition of NR had no positive effect on the butyric acid production, due to the low contribution of electric current to the end-products. With the cathode potential of -0.80 V (vs Ag/AgCl), relative abundance of the butyric acid fermenting bacteria (Clostridium cluster IV and cluster XIVa) in the microbial mixture was increased from 20.25% in the OC system to 33.61% in the CEF system. This research work not only presents a novel method for enhancing butyric acid production by rice straw fermentation, but also aids an understanding of the fermentation mechanism in CEF systems.
生物电化学系统 (BES) 作为一种通用方法，可在收获可持续能源和增值化学品的同时处理环境问题。为了提高从稻草中生产丁酸的效率，本研究构建了微生物燃料电池 (MFC) 和阴极电发酵 (CEF) 系统。在接种相同混合培养物的情况下，分别评估了有/无中性红 (NR) 作为电子介体时两种 BES 的发酵丁酸效率。结果表明，MFC 系统中的丁酸发酵效率较低。而 CEF 系统对丁酸生产有明显的积极影响。CEF 系统中的丁酸产量和比产率分别达到 5.54 g/L 和 0.41 g/g，比开路 (OC) 系统分别提高了 17.37%和 28.13%。在产生的总挥发性脂肪酸 (VFAs) 中，丁酸的质量百分比也从 44.74%增加到 52.76%。由于电流对最终产物的贡献较低，NR 的添加对丁酸生产没有积极影响。在-0.80 V（相对于 Ag/AgCl）的阴极电位下，微生物混合物中丁酸发酵菌（簇 IV 和 XIVa）的相对丰度从 OC 系统中的 20.25%增加到 CEF 系统中的 33.61%。这项研究工作不仅提出了一种通过稻草发酵提高丁酸产量的新方法，还有助于理解 CEF 系统中的发酵机制。
