School of Chemical Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea.
Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA.
Bioelectrochemistry. 2021 Apr;138:107690. doi: 10.1016/j.bioelechem.2020.107690. Epub 2020 Nov 3.
This study examined the obligate aerobe, Pseudomonas putida, using acetate as the sole carbon and energy source, and respiration via an anode as the terminal electron acceptor under anoxic conditions. P. putida showed significantly different acetate assimilation in a closed-circuit microbial fuel cell (CC-MFC) compared to an open circuit MFC (OC-MFC). More than 72% (2.6 mmol) of acetate was consumed during 84 hrs in the CC-MFC in contrast to the no acetate consumption observed in the OC-MFC. The CC-MFC produced 150 μA (87 C) from acetate metabolization. Electrode-based respiration reduced the NADH/NAD ratio anaerobically, which is similar to the aerobic condition. The CC-MFC showed significantly higher acetyl-CoA synthetase activity than the OC-MFC (0.028 vs. 0.001 μmol/min/mg), which was comparable to the aerobic condition (circa 60%). Overall, electrode-based respiration enables P. putida to metabolize acetate under anoxic conditions and provide a platform to regulate the bacterial redox balance without oxygen.
本研究以乙酸盐为唯一碳源和能源，在缺氧条件下通过阳极进行呼吸，考察了专性需氧菌恶臭假单胞菌（Pseudomonas putida）。与开路微生物燃料电池（OC-MFC）相比，在闭路微生物燃料电池（CC-MFC）中，P. putida 的乙酸盐同化作用明显不同。在 CC-MFC 中，84 小时内消耗了超过 72%（2.6 mmol）的乙酸盐，而在 OC-MFC 中则没有观察到乙酸盐消耗。CC-MFC 从乙酸盐代谢中产生了 150 μA（87°C）。基于电极的呼吸在厌氧条件下降低了 NADH/NAD 比，这与有氧条件相似。CC-MFC 的乙酰辅酶 A 合成酶活性（0.028 微摩尔/分钟/毫克）明显高于 OC-MFC（0.001 微摩尔/分钟/毫克），与有氧条件（约 60%）相当。总的来说，基于电极的呼吸使 P. putida 能够在缺氧条件下代谢乙酸盐，并提供一个无需氧气即可调节细菌氧化还原平衡的平台。
