Bidirectional electroactive microbial biofilms and the role of biogenic sulfur in charge storage and release

• Published in: iScience 2021-08, Vol.24 (8), p.102822-102822, Article 102822
• Main Authors: Izadi, Paniz, Gey, Marten Niklas, Schlüter, Nicolas, Schröder, Uwe
• Format: Article
• Language: English
• Subjects: Applied Microbiology; Energy Storage; Energy Systems; Microbiofilms
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2021.102822

The formation of combined electrogenic/electrotrophic biofilms from marine sediments for the development of microbial energy storage systems was studied. Sediment samples from the German coasts of the Baltic and the North Sea were used as inocula for biofilm formation. Anodic biofilm cultivation was applied for a fast and reproducible biofilm formation. North-Sea- and Baltic-Sea-derived biofilms yielded comparable anodic current densities of about 7.2 A m−2. The anodic cultivation was followed by a potential reversal regime, transitioning the electrode potential from 0.2 V to −0.8 V every 2 h to switch between anodic and cathodic conditions. The charge-discharge behavior was studied, revealing an electrochemical conversion of biogenic elemental sulfur as major charge-discharge mechanism. The microbial sequencing revealed strong differences between North- and Baltic-Sea-derived biofilms; however with a large number of known sulfur-converting and electrochemically active bacteria in both biofilms. [Display omitted] •Bidirectional electroactive biofilms are cultivated from marine sediments•Cultivation is based on anodic growth followed by periodic potential reversal•Combined electrogenic and electrotrophic activity is shown•Biogenic, elemental sulfur plays a key role in charge storage and release Applied microbiology; Microbiofilms; Energy systems; Energy storage