Potential regulates metabolism and extracellular respiration of electroactive Geobacter biofilm. Issue 5 (11th February 2019)

• Record Type: Journal Article
• Authors: Li, Dao‐Bo; Li, Jie; Liu, Dong‐Feng; Ma, Xin; Cheng, Lei; Li, Wen‐Wei; Qian, Chen; Mu, Yang; Yu, Han‐Qing
• Is Part Of: Biotechnology and bioengineering. Volume 116:Issue 5(2019)
• Page Start: 961
• Page End: 971
• Publication Date: 2019-02-11
• Subjects: acclimation -- electroactive biofilms -- electrochemical potential -- electron transfer -- Geobacter sulfurreducens -- metabolism; Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.26928
• Languages: English
• ISSNs: 0006-3592

Abstract

Abstract: Dissimilatory metal reducer Geobacter sulfurreducens can mediate redox processes through extracellular electron transfer and exhibit potential‐dependent electrochemical activity in biofilm. Understanding the microbial acclimation to potential is of critical importance for developing robust electrochemically active biofilms and facilitating their environmental, geochemical, and energy applications. In this study, the metabolism and redox conduction behaviors of G. sulfurreducens biofilms developed at different potentials were explored. We found that electrochemical acclimation occurred at the initial hours of polarizing G. sulfurreducens cells to the potentials. Two mechanisms of acclimation were found, depending on the polarizing potential. In the mature biofilms, a low level of biosynthesis and a high level of catabolism were maintained at +0.2 V versus standard hydrogen electrode (SHE). The opposite results were observed at potentials higher than or equal to +0.4 V versus SHE. The potential also regulated the constitution of the electron transfer network by synthesizing more extracellular cytochrome c such as OmcS at 0.0 and +0.2 V and exhibited a better conductivity. These findings provide reasonable explanations for the mechanism governing the electrochemical respiration and activity in G. sulfurreducens biofilms. Abstract : Acclimation of the electrochemically active microbe, Geobacter sulfurreducens, to potential level on microbial metabolism and electron transfer was described in this work. During biofilm formation on inert electrodes, optimized catabolism activity and cytochrome secretion are realized at +0.2 V than higher potentials. The observations and analysis uncovered findings on key factors for more efficient electron output by the electrochemically active biofilms, and suggested their values for engineering bioelectrochemical systems.