Cultivating Electrochemically Active Biofilms at Continuously Changing Electrode Potentials. Issue 8 (23rd April 2019)

• Record Type: Journal Article
• Authors: Riedl, Sebastian; Brown, Robert K.; Alvarez Esquivel, Diana Y.; Wichmann, Hilke; Huber, Katharina J.; Bunk, Boyke; Overmann, Jörg; Schröder, Uwe
• Is Part Of: ChemElectroChem. Volume 6:Issue 8(2019)
• Page Start: 2238
• Page End: 2247
• Publication Date: 2019-04-23
• Subjects: electrochemically active microbial biofilms -- microbial electrochemical technology -- cultivation -- wastewater -- electron transfer kinetics; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201900036
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: In this study, electrochemically active microbial biofilms were cultivated and studied at continuously alternating electrode potentials. Compared to cultivation and operation at a single constant potential, this method enhanced microbial turnover and maximum current densities. Electrochemically active microbial biofilms were cultivated in a multi‐carbon source culture for several biofilm generations and were subsequently fed with real, domestic wastewater. Compared to constant potential cultivation, average ( N =12) biofilm limiting current density at +0.2 V vs. Ag/AgCl increased from 0.350±0.101 to 0.508±0.099 mA cm −2 with a significant reduction in the time required until the maximum current output was reached from 2.01±0.79 to 1.36±0.71 d. The relative increase in maximum current density and decrease in the time required to reach it are similar. The relative differences of higher over lower values are both approximately 45 %. Biofilm community analysis showed a dominance of Geobacteraceae spp . in the electrochemically active biofilms, which is in accordance with the formal potentials derived from cyclic voltammetry. The overall increase in performance is related to the selection of electrochemically active microorganisms, which exhibit local maxima in their electron transfer kinetics between −0.3 and −0.2 V vs. Ag/AgCl. Abstract : Waste not, want not : Effective wastewater treatment using microbial electrochemical technology demands well‐designed cultivation methods. This study shows the successful selection and enrichment of mixed culture biofilms by using previously developed realistic artificial wastewater and now with continuously changing electrode potentials. The improved method yields increased maximum current densities as well as decreased times required to reach it.