A scalable, Rotating Disc Bioelectrochemical Reactor (RDBER) suitable for the cultivation of both cathodic and anodic biofilms

This study discusses the construction and operation of a membrane-less bioelectrochemical reactor that employs rotating working electrodes with a surface area of up to 1 m2. As a proof-of-principle for an aerobic microbial electrosynthesis process, Kyrpidia spormannii was cultivated in the reactor. Optical coherence tomography was used to examine the spatial distribution of the cathodic biofilm. After 24 days 87% of the cathode surface was covered with biofilm that was characterized by a radial increase in its biovolume towards the circumcenter of the electrodes reaching up to 92.13 m3 m-2. To demonstrate the versatility of the system, we further operated the reactor as a microbial electrolysis cell employing a co-culture of Shewanella oneidensis and Geobacter sulfurreducens. Anodic current densities of up to 130 A cm-2 were measured during these batch experiments. This resulted in a maximum production rate of 0.43 liters of pure hydrogen per liter reactor volume and day. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=161 SRC="FIGDIR/small/507646v3_ufig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@102fbecorg.highwire.dtl.DTLVardef@e96345org.highwire.dtl.DTLVardef@7476aaorg.highwire.dtl.DTLVardef@1ac358_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIConstruction of a 10 L membrane-less, pressurizable bioelectrochemical reactor C_LIO_LIRotating working electrodes with up to 1 m2 electrode surface C_LIO_LIElectroautotrophic cultivation and quantification of K. spormannii biofilms C_LIO_LIInitial cell density crucial for successful K. spormannii biofilm formation C_LIO_LIAnodic operation as MEC with Shewanella / Geobacter coculture C_LI