Secretion of Flavins byShewanellaSpecies and Their Role in Extracellular Electron Transfer

• DOI: 10.1128/aem.01387-07
• Publication Date: 2007-12-08T01:53:55Z
• Authors: Harald von Canstein; Jun Ogawa; Sakayu Shimizu; Jonathan R. Lloyd
• Keywords: Shewanella; Electron acceptor; Shewanella oneidensis; Flavin mononucleotide; Electron donor; Flavin adenine dinucleotide

Fe(III)-respiring bacteria such as Shewanella species play an important role in the global cycle of iron, manganese, and trace metals are useful for many biotechnological applications, including microbial fuel cells bioremediation waters sediments contaminated with organics, metals, radionuclides. Several alternative electron transfer pathways have been postulated reduction insoluble extracellular subsurface minerals, Fe(III) oxides, by species. One potential mechanism involves secretion shuttle. Here we identify first time flavin mononucleotide (FMN) riboflavin shuttles produced a range FMN was strongly correlated growth exceeded secretion, which not exclusively associated but maximal stationary phase batch cultures. Flavin adenine dinucleotide predominant intracellular released live cells. The yields were similar under both aerobic anaerobic conditions, total concentrations 2.9 2.1 micromol per gram cellular protein, respectively, after 24 h dissimilatory Fe(III)-reducing conditions when fumarate supplied sole acceptor. flavins shown to act promote anoxic coupled accelerated poorly crystalline oxides. implications living at redox boundaries, where these mineral phases can be significant acceptors growth, discussed.