Cover Picture: The Planktonic Relationship Between Fluid‐Like Electrodes and Bacteria: Wiring in Motion (ChemSusChem 4/2017)

Abstract

The Cover picture shows the bacteria‐electrode interaction between a fluid‐like electrode and planktonic living cells in a microbial electrochemical device. We show for the first time that a biofilm living mode is not a strict requirement for Geobacter sulfurreducens to perform extracellular electron transfer (EET) to an anode, an alternative to the paradigm of microbial EET in which electroactive bacteria colonize an electrically conductive surface to transfer electrons directly to it. More details can be found in the Full Paper by Tejedor‐Sanz et al. on page 693 in Issue 4, 2017 (DOI: 10.1002/cssc.201601329).

Novel electrochemical strategies for the microbial conversion of CO2 into biomass and volatile fatty acids using a fluid‐like bed electrode in a three‐phase reactor

“…To increase electron accessibility by microorganisms and to maximize planktonic bacteria interaction with an electrode, a bed of conductive GC particles was added (Tejedor‐Sanz et al., 2017 ). The GC particles in the reactor thereby acted as a cathode, and the graphite paper's primary purpose was as the current collector.…”

“…A mix of activated sludge and anaerobic digester sludge, taken from an urban wastewater treatment plant (WWTP) located in Guadalajara (Spain), was used as microbial inoculum (Anwer et al., 2021 ). The medium to select and enrich chemolithoautotrophic bacteria was freshwater medium (FWM) NaHCO 3 2.5 g L −1 , NH 4 Cl 0.5 g L −1 , NaH 2 PO 4 ·2H 2 O 0.41 g L −1 , KCl 0.1 g L −1 , a mixed of vitamins 10 mL L −1 , a mixed of minerals 10 mL L −1 (Tejedor‐Sanz et al., 2017 ) and adjusted to pH 6 (pHmeter Crison pH 25). 2 g L −1 of 2‐bromoethanosulfonic acid (BES) (Acros Organics) was added to avoid the growth of methanogens (May et al., 2016 ; Tharak & Venkata Mohan, 2021 ).…”

“…In this particular scenario for finding a suitable bioelectrochemical configuration a new type of bioreactor, the Microbial Electrochemical Fluidized Bed Reactor (ME‐FBR) may offer features to overcome some MES limitations. ME‐FBR originally demonstrated that electroactive microorganisms like those from Geobacter genus could grow under a planktonic state by performing direct extracellular electron transfer to a fluid‐like electrode (Tejedor‐Sanz et al., 2017 ). The combination of a gas column reactor and a bioelectrochemical reactor should address the main problems in the MES reactors studied thus far (Bajracharya et al., 2022 ).…”

“…Also, fluidized bed electrodes moved by gas solve the low solubility of CO 2 /H 2 in the fermentation medium (Bajracharya et al., 2022 ). Furthermore, this mode of operation enhances mass transfer (Tejedor‐Sanz et al., 2017 ). The fact that such a fluid‐like electrode has been successfully validated as a biocathode for reducing nitrate (Tejedor‐Sanz et al., 2020 ) suggests a potential use to support reductive microbial metabolism like those after bioelectrosynthesis.…”