This study demonstrates the impact outer membrane permeability has on the power densities generated by E. coli-based microbial fuel cells with neutral red as the mediator, and how increasing the permeability improves the current generation. Experiments performed with several lipopolysaccharide (LPS) mutants (ΔwaaC, ΔwaaF and ΔwaaG) of E. coli BW25113 that increase the outer membrane permeability found the power generated by two of the truncated LPS mutants, i.e., ΔwaaC and ΔwaaF, to be significantly higher (5.6 and 6.9 mW/m², respectively) than that of the wild-type E. coli BW25113 (2.6 mW/m²). Branched polyethyleneimine (BPEI, 400 mg/L), a strong chemical permeabilizer, was more effective, however, increasing the power output from E. coli BW25113 cultures to as much as 29.7 mW/m², or approximately 11-fold higher than the control MFC. BPEI also increased the activities of the mutant strains (to between 10.6 and 16.3 mW/m²), as well as when benzyl viologen was the mediator. Additional tests found BPEI not only enhanced membrane permeability but also increased the zeta potential of the bacterial cells from a value of −43.4 mV to −21.0 mV. This led to a significant increase in auto-aggregation of the bacterial cells and, consequently, better adherence of the cells to the anode electrode, as was demonstrated using scanning electron microscopy. In conclusion, our study demonstrates the importance of outer membrane permeabilities on MFC performances and defines two benefits that BPEI offers when used within MFCs as an outer membrane permeabilizer.

这项研究证明了外膜渗透性对以中性红为媒介的大肠杆菌微生物燃料电池产生的功率密度的影响，以及提高渗透性如何改善电流产生。实验与几个脂多糖（LPS）的突变体（Δ进行waaC，Δ WAAF和Δ WAAG的）大肠杆菌BW25113增加外膜渗透性发现所产生的电力由两个截短LPS突变体，即，Δ waaC和Δ WAAF，比野生型大肠杆菌要高得多（分别为5.6和6.9 mW / m ²）BW25113（2.6 mW / m ²）。支链聚乙烯亚胺（BPEI，400 mg / L），一种强的化学通透剂，更有效，但是，将大肠杆菌BW25113培养物的输出功率提高到29.7 mW / m ²，大约是其的11倍。控制MFC。BPEI还增加了突变菌株的活性（至10.6至16.3 mW / m ^2之间）），以及苄基紫精为介体的时间。其他测试发现BPEI不仅增强了膜的通透性，而且还使细菌细胞的Zeta电位从-43.4 mV增至了-21.0 mV。如使用扫描电子显微镜所证实的，这导致细菌细胞的自动聚集显着增加，并且因此导致细胞对阳极电极的更好粘附。总之，我们的研究证明了外膜渗透性对MFC性能的重要性，并定义了BPEI在MFC中用作外膜渗透剂时提供的两个好处。