Improved Microbial Fuel Cell Performance by Engineering E. coli for Enhanced Affinity to Gold

Abstract

Microorganism affinity for surfaces can be controlled by introducing material binding motifs into proteins such as fimbrial tip and outer membrane proteins. Here, controlled surface affinity is used to manipulate and enhance electrical power production in a typical bioelectrochemical system, a microbial fuel cell (MFC). Specifically, gold-binding motifs of various affinity were introduced into two scaffolds in Escherichia coli: eCPX, a modified version of outer membrane protein X (OmpX), and FimH, the tip protein of the fimbriae. The behavior of these strains on gold electrodes was examined in small-scale (240 µL) MFCs and 40 mL U-tube MFCs. A clear correlation between the affinity of a strain for a gold surface and the peak voltage produced during MFC operation is shown in the small-scale MFCs; strains displaying peptides with high affinity for gold generate potentials greater than 80 mV while strains displaying peptides with minimal affinity to gold produce potentials around 30 mV. In the larger MFCs, E. coli strains with high affinity to gold exhibit power densities up to 0.27 mW/m2, approximately a 10-fold increase over unengineered strains lacking displayed peptides. Moreover, in the case of the modified FimH strains, this increased power production is sustained for five days.

Scalable Production of Peptides for Enhanced Struvite Formation via Expression on the Surface of Genetically Engineered Microbes

“…The biterminal display enables the use of a second peptide, located at the opposite terminus, for detection of expression. This membrane protein system has been used for a variety of applications, including bacteria–nanoparticle hybrid materials, 24 high-affinity peptide screening, 25 and microbial fuel cells, 26 but has not been utilized in the context of struvite precipitation or phosphate recovery. To precipitate struvite, E. coli was allowed to grow overnight in the presence of added magnesium or both magnesium and phosphate.…”

Effect of Glucose and Methylene Blue in Microbial Fuel Cells Using E. coli

“…E. coli DH5α is a widely used strain for maintaining and amplifying plasmid DNA [18]. Its effective utilization in microbial cells can facilitate initiatives to expand its application through improvements aimed at achieving a higher efficiency in electron transfer, as has been done recently [19,20].…”