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

doi:10.1016/j.isci.2023.106065

Electro-polarization of protein-like substances accelerates trans-cell-wall electron transfer in microbial extracellular respiration

iScience. 2023 Feb 1;26(2):106065. doi: 10.1016/j.isci.2023.106065. eCollection 2023 Feb 17.

Authors

Qilin Yu¹, Haohao Mao¹, Bowen Yang¹, Yahui Zhu¹, Cheng Sun¹, Zhiqiang Zhao¹, Yang Li², Yaobin Zhang¹

Affiliations

¹ Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
² School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning 124221, China.

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.

Keywords: Bio-electrochemistry; Biological sciences; Cell biology; Chemistry; Electrochemistry.