Feng Xinyu, Wang Lan, Chen Hongzhang
State Key Laboratory of Biochemical Engineering, Beijing Key Laboratory of Biomass Refining Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Biotechnol Biofuels Bioprod. 2022 May 2;15(1):42. doi: 10.1186/s13068-022-02138-6.
Electric energy is not collected and utilized in biobutanol fermentation. The reason is that the yields of electron shuttles and nanowires are not enough to gather and transfer all electrons to the electrode in liquid fermentation. However, the solid matrix of the adsorption carrier may be conducive to the collection and transfer of electrons because of its good adsorption and conductivity. Therefore, this first-attempt study coupled microbial fuel cell (MFC) with adsorption carrier solid-state fermentation (ACSF). In addition, the effect and mechanism of adsorption carrier solid-state fermentation on power generation were explored.
The power generation performance and fermentation performance were improved by ACSF. The power density by polyurethane and carbon felt carrier solid-state fermentation (PC) was 12 times that by no carrier fermentation (NC). The biobutanol yield of absorbent cotton and carbon felt carrier solid-state fermentation (ACC) was increased by 36.86%. Moreover, the mechanism was explored via metabolic flux analysis, cyclic voltammetry and scanning electron microscopy. The results of metabolic flux analysis showed that more electrons were produced and more carbon flowed to biobutanol production. The cyclic voltammetry results revealed that more riboflavin was produced to enhance extracellular electron transport (EET) by ACSF. The scanning electron microscopy image showed that the adsorption capacity and aggregation degree of bacteria were increased on the electrode and nanowires were observed by ACSF.
A new fermentation mode was established by coupling MFC with ACSF to improve substrate utilization, which will provide crucial insights into the fermentation industry. In addition, the ACSF is an effective method to enhance power generation performance and fermentation performance.
生物丁醇发酵过程中电能未被收集和利用。原因在于电子穿梭体和纳米线的产量不足以在液体发酵中将所有电子收集并转移至电极。然而，吸附载体的固体基质因其良好的吸附性和导电性，可能有利于电子的收集和转移。因此，本首次尝试研究将微生物燃料电池（MFC）与吸附载体固态发酵（ACSF）相结合。此外，还探究了吸附载体固态发酵对发电的影响及机制。
ACSF提高了发电性能和发酵性能。聚氨酯和碳毡载体固态发酵（PC）的功率密度是无载体发酵（NC）的12倍。脱脂棉和碳毡载体固态发酵（ACC）的生物丁醇产量提高了36.86%。此外，通过代谢通量分析、循环伏安法和扫描电子显微镜对机制进行了探究。代谢通量分析结果表明产生了更多电子，且更多碳流向生物丁醇的生成。循环伏安法结果显示ACSF产生了更多核黄素以增强细胞外电子传递（EET）。扫描电子显微镜图像表明ACSF使电极上细菌的吸附能力和聚集程度增加，且观察到了纳米线。
通过将MFC与ACSF相结合建立了一种新的发酵模式，以提高底物利用率，这将为发酵工业提供关键见解。此外，ACSF是提高发电性能和发酵性能的有效方法。
