title: Metabolic Characteristics of a Glucose-Utilizing Shewanella oneidensis Strain Grown under Electrode-Respiring Conditions.
abstract: In bioelectrochemical systems, the electrode potential is an important parameter affecting the electron flow between electrodes and microbes and microbial metabolic activities. Here, we investigated the metabolic characteristics of a glucose-utilizing strain of engineered Shewanella oneidensis under electrode-respiring conditions in electrochemical reactors for gaining insight into how metabolic pathways in electrochemically active bacteria are affected by the electrode potential. When an electrochemical reactor was operated with its working electrode poised at +0.4 V (vs. an Ag/AgCl reference electrode), the engineered S. oneidensis strain, carrying a plasmid encoding a sugar permease and glucose kinase of Escherichia coli, generated current by oxidizing glucose to acetate and produced D-lactate as an intermediate metabolite. However, D-lactate accumulation was not observed when the engineered strain was grown with a working electrode poised at 0 V. We also found that transcription of genes involved in pyruvate and D-lactate metabolisms was upregulated at a high electrode potential compared with their transcription at a low electrode potential. These results suggest that the carbon catabolic pathway of S. oneidensis can be modified by controlling the potential of a working electrode in an electrochemical bioreactor.
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Nakagawa
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kouzuma
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Atsumi
authors.initials: A
authors.lastname: Hirose
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kasai
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Yoshida
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000085:Acetates / Q000378:metabolism; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods; D019149:Bioreactors / Q000382:microbiology*; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D004734:Energy Metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering; D005947:Glucose / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics; D010084:Oxidation-Reduction; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020592:Shewanella / Q000235:genetics / Q000378:metabolism*
chemical_list: D000085:Acetates; D029968:Escherichia coli Proteins; D007773:Lactates; D026901:Membrane Transport Proteins; D010770:Phosphotransferases; D005947:Glucose