A method for high throughput bioelectrochemical research based on small scale microbial electrolysis cells.

Area of Science:

• Bioelectrochemistry
• Microbial Electrogenesis
• Environmental Microbiology

Background:

• Studying exoelectrogenic microorganisms is crucial but often hindered by expensive equipment and specialized reactors.
• Existing methods lack the scalability required for high-throughput analysis of microbial electrochemical processes.

Purpose of the Study:

• To develop a simple, cost-effective, and high-throughput system for bioelectrochemical research using microbial electrolysis cells (MECs).
• To evaluate the performance of different cathode materials and buffer conditions for exoelectrogenesis.
• To compare the performance of pure and mixed exoelectrogenic cultures in the developed system.

Main Methods:

• Construction of inexpensive MECs (5 mL serum bottles) with graphite anodes and various cathode materials (SS mesh, graphite, SS wire, Pt wire).
• Operation of multiple MECs in parallel using a single power source for high-throughput screening.
• Testing different buffer solutions (phosphate and bicarbonate) and inocula (pure and mixed exoelectrogenic cultures).

Main Results:

• A stainless steel (SS) mesh cathode yielded the highest volumetric current density (240 A/m³) with a wastewater inoculum.
• Parallel operation of MECs did not compromise performance, enabling scalable reactor operation (>1000 reactors).
• Phosphate buffer (50 mM) supported higher current densities than bicarbonate buffer (30 mM) for both pure and mixed cultures; only mixed cultures sustained current in 200 mM phosphate buffer.

Conclusions:

• The developed inexpensive MEC system is effective for high-throughput bioelectrochemical research.
• The system facilitates in-depth examination of exoelectrogenic microorganisms, including pure and mixed cultures.
• Buffer composition significantly impacts exoelectrogenesis, with phosphate buffers showing superior performance in this setup.