Understanding how nonelectroactive bacteria (non-EAB) perceive and respond to electro-stimulation is pivotal for optimizing electro-biostimulation systems. Here, Escherichia coli, a representative non-EAB, was employed to investigate its electrical response behavior and molecular regulatory mechanism across a spectrum of current densities. Accelerated bacterial growth was observed at current densities ranging from 2 to 10 A m^–2 with a maximum growth rate of 1.89 h^–1 at 10 A m^–2. Moderate electrostimulation (10 A m^–2) promoted NADH regeneration and adenosine triphosphate synthesis by modulating intracellular glycolytic flux, tricarboxylic acid (TCA) cycle and electron transport chain (ETC), while cells became inactivated at 20 A m^–2 mainly due to the overall inhibition of the TCA cycle and domino collapse of ETC. The presence of reductive stress caused by electro-stimulation not only promoted NADPH and glutamine consumption but also impacted the material exchange fluxes by altering outer membrane proteins (OMPs) from β-fold to β-corner. Additionally, extracellular polymeric substances served as the electron transient medium to sense electro-stimulation. The study revealed that non-EAB possessed approaches different from EET to sense and respond to electro-stimulation. The improved comprehension of regulatory mechanisms governing catabolic pathways under electro-stimulation holds promise for developing more efficient electro-biostimulation systems, with implications for environmental biotechnology applications.

中文翻译：

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非电活性细菌对电刺激反应的分子洞察：生长和代谢调节机制

了解非电活性细菌 (non-EAB) 如何感知和响应电刺激对于优化电生物刺激系统至关重要。在这里，采用代表性的非 EAB大肠杆菌来研究其在一系列电流密度范围内的电响应行为和分子调节机制。在 2 至 10 A m ^–2的电流密度范围内观察到细菌生长加速， 10 A m ^–2时的最大生长速率为 1.89 h ^–1。中度电刺激（10 A m ^–2）通过调节细胞内糖酵解通量、三羧酸（TCA）循环和电子传递链（ETC）促进 NADH 再生和三磷酸腺苷合成，而细胞在 20 A m ^–2时失活，主要是由于TCA循环的整体抑制和ETC的多米诺骨牌倒塌。电刺激引起的还原应激不仅促进了 NADPH 和谷氨酰胺的消耗，而且还通过将外膜蛋白 (OMP) 从 β 折叠改变为 β 角来影响物质交换通量。此外，细胞外聚合物质充当电子瞬态介质来感测电刺激。研究表明，非 EAB 拥有与 EET 不同的方法来感知和响应电刺激。对电刺激下控制分解代谢途径的调节机制的更好理解有望开发更有效的电生物刺激系统，并对环境生物技术应用产生影响。