Fe(III) oxide respiration by a Desulfovibrio species lacking canonical outer-membrane electron transfer systems.

Desulfovibrio strain JY can reduce Fe(III) oxides and conserve energy without genes for canonical outer-membrane electron transfer systems, using a flavin electron shuttle.

• Why it matters: Understanding microbial Fe(III) reduction is crucial for biogeochemical cycling, but current models rely on known gene markers that may overlook diverse mechanisms. This work highlights a gap in predicting electroactive microbes based solely on genome data.
• What they did: The study examined Desulfovibrio strain JY's ability to reduce Fe(III) oxides using H2 or lactate, measuring reduction rates, shuttle production, and gene expression, especially focusing on flavin export genes during Fe(III) respiration.
• The result: Findings show strain JY employs self-produced flavin shuttles to reduce Fe(III) oxides without typical outer-membrane cytochromes, suggesting a broader microbial diversity in extracellular electron transfer mechanisms than previously recognized.