title: Mitochondrial origin of extracelullar transferred electrons in yeast-based biofuel cells.
abstract: The influence of mitochondrial electron transport chain inhibitors on the electricity outputs of Candida melibiosica yeast-based biofuel cell was investigated. The addition of 30 μM rotenone or antimycin A to the yeast suspension results in a decrease in the current generation, corresponding to 25.7±1.3%, respectively 38.8±1.9% reduction in the electric charge passed through the bioelectrochemical system. The latter percentage coincides with the share of aerobic respiration in the yeast catabolic processes, determined by the decrease of the ethanol production during cultivation in the presence of oxygen compared with that obtained under strict anaerobic conditions. It was established that the presence of both inhibitors leads to almost complete mitochondrial dysfunction, expressed by inactivation of cytochrome c oxidase and NADH:ubiquinone oxidoreductase as well as reduced electrochemical activity of isolated yeast mitochondria. It was also found that methylene blue partially neutralized the rotenone poisoning, probably serving as alternative intracellular electron shuttle for by-passing the complex I blockage. Based on the obtained results, we suppose that electrons generated through the aerobic respiration processes in the mitochondria participate in the extracellular electron transfer from the yeast cells to the biofuel cell anode, which contributes to higher current outputs at aerobic conditions.
authors.affiliation: Department of Biochemistry and Microbiology, "Paisii Hilendarski" University of Plovdiv, 24 Tzar Asen Str., 4000 Plovdiv, Bulgaria. Electronic address: jolinahubenova@yahoo.com.
authors.forename: Yolina
authors.initials: Y
authors.lastname: Hubenova
authors.affiliation: Department of Chemistry, South-West University "Neofit Rilski", 66 Ivan Mihajlov Str., 2700 Blagoevgrad, Bulgaria. Electronic address: mitovmario@mail.bg.
authors.forename: Mario
authors.initials: M
authors.lastname: Mitov
mesh_terms: D000968:Antimycin A / Q000494:pharmacology; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D002175:Candida / Q000166:cytology*; D004553:Electric Conductivity; D004579:Electron Transport / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000968:Antimycin A
keywords: Electron transport chains; Extracellular electron transfer; Inhibition; Mitochondria; Yeast-based biofuel cell