Combining Geobacter spp. Dominated Biofilms and Anaerobic Digestion EffluentsThe Effect of Effluent Composition and Electrode Potential on Biofilm Activity and Stability

• Published in: Environmental science & technology Vol. 57; no. 6; pp. 2584 - 2594
• Main Authors: Dzofou Ngoumelah, Daniel, Kuchenbuch, Anne, Harnisch, Falk, Kretzschmar, Jörg
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.02.2023
• Subjects: Anaerobic digestion; Anaerobic microorganisms; Anaerobiosis; Archaea; Bioelectric Energy Sources; Biofilms; DNA sequencing; Effluents; Electrochemistry; Electrodes; Geobacter; Methanogenic archaea; Methanogenic bacteria; Microorganisms; rRNA 16S; Stability; Sustainability; Sustainable Systems; applied anode potential; microbial electrochemical technologies; anaerobic digestion; Geobacter spp. dominated biofilm; methanogens
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.2c07574

The combination of anaerobic digestion (AD) and microbial electrochemical technologies (METs) offers different opportunities to increase the efficiency and sustainability of AD processes. However, methanogenic archaea and/or particles may partially hinder combining MET and AD processes. Furthermore, it is unclear if the applied anode potential affects the activity and efficiency of electroactive microorganisms in AD-MET combinations as it is described for more controlled experimental conditions. In this study, we confirm that 6-week-old Geobacter spp. dominated biofilms are by far more active and stable in AD-effluents than 3-week-old Geobacter spp. dominated biofilms. Furthermore, we show that the biofilms are twice as active at −0.2 V compared to 0.4 V, even under challenging conditions occurring in AD-MET systems. Paired-end amplicon sequencing at the DNA level using 16S-rRNA and mcrA gene shows that hydrogenotrophic methanogens incorporate into biofilms immersed in AD-effluent without any negative effect on biofilm stability and electrochemical activity.