Microbial Electroreduction: Screening for New Cathodic Biocatalysts

Cathodic microbial electrocatalysis, where microorganisms consume electrons from a cathode to perform biochemical reductions, is currently of high interest. For an effective electrochemical screening of potential new cathode biocatalysts, we developed a time‐saving medium‐throughput potentiostatic BES system to evaluate microbial ability to accept reducing equivalents from an electrode in pure cultures. Of nine tested physiologically and phylogenetically different strains, five promising cathode‐active strains were identified: Acidithiobacillus ferrooxidans ( j max =−50 μA cm −2 ), Desulfosporosinus orientis ( j max =−4 μA cm −2 ), Thiobacillus denitrificans and Sulfurimonas denitrificans ( j max =−2 μA cm −2 for both), and Desulfovibrio piger ( j max =−1.5 μA cm −2 ). From this screening, hypotheses were formulated on possible electron consumption and utilization processes. This work serves as a foundation for deeper investigation and characterization of the identified cathode biocatalysts.