Secretion of flavins by Shewanella species and their role in extracellular electron transfer

Flavin mononucleotide (FMN) and riboflavin are identified as the extracellular electron shuttles that are produced by a range of Fe(III)-respiring bacteria such as Shewanella species. The implications of flavin secretion by Shewanella cells living at redox boundaries and their role in extracellular electron transfer are analyzed.