Characterization of electrochemically active bacteria utilizing a high-throughput voltage-based screening assay.

Area of Science:

• Microbiology
• Electrochemistry
• Bioengineering

Background:

• Traditional metal reduction assays for electrochemically active bacteria (EAB) lack definitive correlation with microbial fuel cell (MFC) performance.
• A need exists for reliable, high-throughput screening methods to characterize EAB for MFC applications.

Purpose of the Study:

• To develop and validate a high-throughput voltage-based screening assay (VBSA) for EAB.
• To assess the VBSA's ability to monitor bacterial growth and identify effective electron donors for MFCs.

Main Methods:

• Designed a prototype four- to nine-well VBSA using MFC engineering principles and a universal cathode.
• Generated bacterial growth curves for Shewanella oneidensis strains DSP10 and MR-1 by monitoring open circuit voltage and current.
• Tested eight different organic electron donors with S. oneidensis MR-1 under aerobic conditions.

Main Results:

• VBSA generated bacterial growth curves with high correlation (within 5% deviation) to established doubling times for Shewanella.
• The assay demonstrated the capacity to monitor fundamental EAB life cycle properties.
• Under oxygen exposure, S. oneidensis MR-1 generated current in response to acetate, lactate, and glucose additions.

Conclusions:

• The VBSA is a reliable and high-throughput tool for characterizing EAB, overcoming limitations of traditional metal reduction assays.
• The assay effectively monitors bacterial growth and identifies optimal electron donors for enhanced MFC performance.
• Findings contribute to the advancement of EAB selection and application in microbial fuel cells.