Enhanced microbial electrosynthesis performance with 3-D algal electrodes under high CO₂ sparging: Superior biofilm...

Microbial electrosynthesis (MES) shows great promise for converting CO₂ into high-value chemicals. However, cathode biofilm erosion by high CO₂ sparging and the unclear role of plankton in MES hinders the continuous improvement of its performance. This study aims to enhance biofilm resistance and improve interactions between bio-cathode and plankton by upgrading waste algal biomass into 3-D porous algal electrode (PAE) with rough surface. Results showed that the acetate synthesis of PAE under 20 mL/min CO₂ sparging (PAE-20) was up to 3330.61 mol/m³, 4.63 times that of carbon felt under the same conditions (CF-20). The microbial loading of PAE-20 biofilm was twice that of CF-20. Furthermore, higher cumulative abundance of functional microorganisms was observed in plankton of PAE-20 (55 %), compared to plankton of CF-20 (14 %), and enhanced biocathode-plankton interactions significantly suppressed acetate consumption. Thus, this efficient and sustainable 3-D electrode advances MES technology and offers new perspectives for waste biomass recycling.