Boosting mediated electron transfer in bioelectrochemical systems with tailored defined microbial cocultures

Area of Science:

• Microbiology
• Electrochemistry
• Bioenergy

Background:

• Bioelectrochemical systems (BES) utilize microbial catalysts for sustainable energy generation from organic matter.
• Understanding electrode microbial communities is key to improving current generation in BES.
• Electron mediator-producing microorganisms, like Pseudomonas aeruginosa, are crucial for efficient electricity generation.

Purpose of the Study:

• To enhance synergistic effects in defined cocultures of P. aeruginosa and E. aerogenes for high current production in BES.
• To investigate the impact of environmental parameters on coculture behavior and electricity generation.
• To establish conditions for long-term, high-density current production in BES.

Main Methods:

• Cultivating defined cocultures of P. aeruginosa and E. aerogenes.
• Optimizing process parameters including pH, temperature, oxygen supply, and substrate requirements.
• Operating the coculture in fed-batch mode for extended periods.

Main Results:

• Optimizing oxygen supply enhanced electric current production by over 400%.
• Fed-batch operation achieved very high current densities and sustained energy harvesting for 1 month.
• Coulombic efficiency reached 20%, an outstanding result for mediator-based electron transfer.

Conclusions:

• Process parameter optimization, particularly oxygen supply, significantly enhances synergistic microbial coculture performance in BES.
• This study provides a foundation for rationally designing cocultures in BES for bioenergy generation and bioprocess sensing.
• Controlled bioprocess conditions are essential for harnessing the synergistic effects of microbial cocultures in BES.