Characterization of Electrogenic Gut Bacteria

Area of Science:

• Microbiology
• Bioelectrochemistry
• Gut Microbiome

Background:

• Electrogenic Gram-negative bacteria in anaerobic environments are well-studied.
• Gram-positive bacteria were historically considered weak exoelectrogens due to their cell walls.
• Recent findings highlight electrogenicity in Gram-positive pathogens, prompting investigation into gut microbiota.

Purpose of the Study:

• To characterize the extracellular electron-transfer capabilities of five key gut bacteria.
• To explore the potential of Gram-positive bacteria as exoelectrogens for novel applications.
• To develop a screening method for identifying electrogenic gut bacteria and their pathways.

Main Methods:

• Utilized a 21-well paper-based microbial fuel cell array for high-throughput screening.
• Assessed electrogenic capabilities of *Staphylococcus aureus*, *Enterococcus faecalis*, *Streptococcus agalactiae*, *Lactobacillus reuteri*, and *Lactobacillus rhamnosus*.
• Initiated a transposon screen to identify genes involved in electrogenicity in *S. aureus*.

Main Results:

• *Staphylococcus aureus*, *Enterococcus faecalis*, and *Streptococcus agalactiae* demonstrated significant electrogenic capabilities.
• Power generation by these Gram-positive bacteria was comparable to the known exoelectrogen *Shewanella oneidensis*.
• The developed microbial fuel cell array proved effective for simultaneous characterization of bacterial electrogenicity.

Conclusions:

• Gram-positive gut bacteria possess notable electrogenic potential, challenging previous assumptions.
• This research paves the way for developing bio-powered implantable devices and gastrointestinal biosensors.
• Identified key electrogenic Gram-positive species and initiated genetic analysis of electron transfer pathways.