title: Temporal-spatial changes in viabilities and electrochemical properties of anode biofilms.
abstract: Sustained current generation by anodic biofilms is a key element for the longevity and success of bioelectrochemical systems. Over time, however, inactive or dead cells can accumulate within the anode biofilm, which can be particularly detrimental to current generation. Mixed and pure culture (Geobacter anodireducens) biofilms were examined here relative to changes in electrochemical properties over time. An analysis of the three-dimensional metabolic structure of the biofilms over time showed that both types of biofilms developed a live outer-layer that covered a dead inner-core. This two-layer structure appeared to be mostly a result of relatively low anodic current densities compared to other studies. During biofilm development, the live layer reached a constant thickness, whereas dead cells continued to accumulate near the electrode surface. This result indicated that only the live outer-layer of biofilm was responsible for current generation and suggested that the dead inner-layer continued to function as an electrically conductive matrix. Analysis of the electrochemical properties and biofilm thickness revealed that the diffusion resistance measured using electrochemical impedance spectroscopy might not be due to acetate or proton diffusion limitations to the live layer, but rather electron-mediator diffusion.
authors: †State Key Laboratory of Clean Energy Utilization, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, P.R. China.
authors: Dan
authors: D
authors: Sun
authors: †State Key Laboratory of Clean Energy Utilization, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, P.R. China.
authors: Shaoan
authors: S
authors: Cheng
authors: ‡Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, China Academy of Sciences, Beijing, China.
authors: Aijie
authors: A
authors: Wang
authors: †State Key Laboratory of Clean Energy Utilization, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, P.R. China.
authors: Fujian
authors: F
authors: Li
authors: §Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors: Bruce E
authors: BE
authors: Logan
authors: †State Key Laboratory of Clean Energy Utilization, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, P.R. China.
authors: Kefa
authors: K
authors: Cen
mesh_terms: D000085:Acetates / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development; D058266:Dielectric Spectroscopy; D004566:Electrodes; D004583:Electrons; D045302:Geobacter / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D062211:Spatio-Temporal Analysis
chemical_list: D000085:Acetates