Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China.
Environ Sci Technol. 2013 Oct 1;47(19):11199-205. doi: 10.1021/es402132r. Epub 2013 Sep 20.
1,3-Propanediol (1,3-PDO) can be produced biologically through glycerol fermentation. While such a process typically involves a pure culture system, particularly for crude glycerol, there would be operational advantages if a mixed population could be used. However, in the latter case the yield is typically low. Here, we use electrical current as the driving force for a mixed population fermenting glycerol in the cathode of a microbial bioelectrochemical system (BES). The carbon and electron flows were monitored by a titration and off-gas analysis (TOGA) sensor, and the syntrophic interactions in the BES were also investigated. Results show that on a carbon yield basis, current enhanced 1,3-PDO production from 24.8% (without current) to 50.1% (with a polarized biocathode at -0.9 V versus standard hydrogen electrode, SHE). Flux analysis indicated that the reductive current can be integrated into glycerol metabolism to enhance 1,3-PDO yield and that glycerol metabolism was redirected from propionate fermentation to 1,3-PDO production. A polarization of -0.6 V (vs SHE) resulted in more fermentative hydrogen production (from 2.7% to 8.0% on electron basis). 1,3-PDO production was also enhanced with hydrogen supply (37.7% on carbon basis), by suppressing hydrogen fermentation. Moreover, interspecies hydrogen transfer encouraged hydrogenotrophic methanogenesis, which was also accelerated by the cathodic polarization.
1,3-丙二醇（1,3-PDO）可以通过甘油发酵生物合成。虽然这种方法通常涉及纯培养系统，特别是对于粗甘油，但如果可以使用混合种群，则会有操作优势。然而，在后一种情况下，产率通常较低。在这里，我们使用电流作为驱动力，通过微生物生物电化学系统（BES）的阴极使甘油在混合种群中发酵。通过滴定和废气分析（TOGA）传感器监测碳和电子流，还研究了 BES 中的共栖相互作用。结果表明，在碳产率的基础上，电流将 1,3-PDO 的产量从 24.8%（无电流）提高到 50.1%（在相对于标准氢电极的-0.9 V 下极化生物阴极）。通量分析表明，还原电流可以整合到甘油代谢中，以提高 1,3-PDO 的产率，并且甘油代谢从丙酸发酵重新定向到 1,3-PDO 生产。在相对于 SHE 的-0.6 V 下极化会导致更多的发酵性氢气产生（基于电子的 2.7%到 8.0%）。通过抑制氢气发酵，氢气供应（基于碳的 37.7%）也可以提高 1,3-PDO 的产量。此外，种间氢转移促进了氢营养型甲烷生成，阴极极化也加速了这一过程。
