Electro-polarization of protein-like substances accelerates trans-cell-wall electron transfer in microbial extracellular respiration
Qilin Yu, Haohao Mao, Bowen Yang, Yahui Zhu, Cheng Sun, Zhiqiang Zhao, Yang Li, Yaobin Zhang
Abstract
Electrical stimulation has been used to strengthen microbial extracellular electron transfer (EET), however, the deep-seated reasons remain unclear. Here we reported that Bacillus subtilis , a typical gram-positive bacterium capable of extracellular respiration, obtained a higher EET capacity after the electrical domestication. After the electrical domestication, the current generated by the EET of B. subtilis was 23.4-fold that of the control group without pre-domestication. Multiple lines of evidence in bacterial cells of B. subtilis , their cell walls, and a model tripeptide indicated that the polarization of amide groups after the electrical stimulation forwarded the H-bonds recombination and radical generation of protein-like substances to develop extracellular electron transfer via the proton-coupled pattern. The improved electrochemical properties of protein-like substances benefited the trans -cell-wall electron transfer and strengthen extracellular respiration. This study was the first exploration to promote microbial extracellular respiration by improving the electrochemical properties of protein-like substances in cell envelopes.