Electrochemical Analysis ofShewanella oneidensisEngineered To Bind Gold Electrodes

Abstract

Growth in three-electrode electrochemical cells allows quantitative analysis of mechanisms involved in electron flow from dissimilatory metal reducing bacteria to insoluble electron acceptors. In these systems, gold electrodes are a desirable surface to study the electrophysiology of extracellular respiration, yet previous research has shown that certain Shewanella species are unable to form productive biofilms on gold electrodes. To engineer attachment of Shewanella oneidensis to gold, five repeating units of a synthetic gold-binding peptide (5rGBP) were integrated within an Escherichia coli outer membrane protein, LamB, and displayed on the outer surface of S. oneidensis. Expression of LamB-5rGBP increased cellular attachment of S. oneidensis to unpoised gold surfaces but was also associated with the loss of certain outer membrane proteins required for extracellular respiration. Loss of these outer membrane proteins during expression of LamB-5rGBP decreased the rate at which S. oneidensis was able to reduce insoluble iron, riboflavin, and electrodes. Moreover, poising the gold electrode resulted in repulsion of the engineered cells. This study provides a strategy to specifically immobilize bacteria to electrodes while also outlining challenges involved in merging synthetic biology approaches with native cellular pathways and cell surface charge.

Real‐Time Label‐Free Monitoring of Shewanella oneidensis MR‐1 Biofilm Formation on Electrode During Bacterial Electrogenesis Using Scanning Electrochemical Microscopy

“…A redox peak Special Issue MATRAFÜRED www.electroanalysis.wiley-vch.decentered at À0.128 V vs. Ag/AgCl filled with saturated KCl (+ 0.197 V vs. SHE) was observed after 24 hours incubation. This peak range is common for adhered membrane protein and cytochromes [21,33]. So existence of this peak proved the effective direct electron transfer through bacteria membrane to adhering electrode surface, consistent with the stable current generation after 20 hours of incubation.…”

Biofabrication of Fe nanoparticles in aqueous extract of Hibiscus sabdariffa with enhanced photocatalytic activities

“…They enable an array of potential applications in materials science, electronics, optics, medicine, biomedical science and engineering and catalysis. [3][4][5] Among magnetic metallic nanomaterials, iron nanoparticles have gained considerable attention for site remediation and the treatment of water polluted by organic and inorganic contaminants because of the higher inherent reactivity of their surface sites. 6 Iron nanoparticles have unique characteristics that include suitability for environmental remediation, 7 high efficiency for the degradation of aqueous organic solutes, 8,9 catalytic activity, 10 and optical, 11 electronic, 12 and antibacterial properties.…”

Towards patterned bioelectronics: facilitated immobilization of exoelectrogenic Escherichia coli with heterologous pili

“…The heterologous production of recombinant outer membrane proteins in the host S. oneidensis has been reported to adversely affect the production of the outer membrane protein complex MtrCAB (Kane et al ., 2013). To test whether this is also true in the case of added Fim pili in the exoelectrogenic E. coli strains, we cultivated the four E. coli strains Kan R ‐Sm R , fim ‐Kan R , cymA ‐ mtr ‐Sm R and cymA ‐ mtr ‐ fim in BES's under anaerobic conditions overnight at a working electrode potential of +200 mV versus Ag/AgCl.…”

“…This may be done by, for instance, patterning of a biosensor surface with a synthetic biofilm consortium that can detect and process multiple signals in parallel. The attachment of current‐producing bacteria on conductive surfaces was attempted previously using gold‐binding peptides that were integrated with an E. coli outer membrane protein and displayed on the outer surface of S. oneidensis (Kane et al ., 2013). This system failed to maintain current production while introducing binding and, thereby, no strategy is currently available for achieving patterning with exoelectrogenic bacteria.…”