Bioelectrochemical systems (BESs) is a term that encompasses a group of novel technologies able to interconvert electrical energy and chemical energy by means of a bioelectroactive biofilm. Microbial electrosynthesis (MES) systems, which branch off from BESs, are able to convert CO₂ into valuable organic chemicals and fuels. This study demonstrates that CO₂ reduction in MES systems can be enhanced by enriching the inoculum and improving CO₂ availability to the biofilm. The proposed system is proven to be a repetitive, efficient, and selective way of consuming CO₂ for the production of acetic acid, showing cathodic efficiencies of over 55% and CO₂ conversions of over 80%. Continuous recirculation of the gas headspace through the catholyte allowed for a 44% improvement in performance, achieving CO₂ fixation rates of 171 mL CO₂ L⁻¹·d⁻¹, a maximum daily acetate production rate of 261 mg HAc·L⁻¹·d⁻¹, and a maximum acetate titer of 1957 mg·L⁻¹. High-throughput sequencing revealed that CO₂ reduction was mainly driven by a mixed-culture biocathode, in which Sporomusa and Clostridium, both bioelectrochemical acetogenic bacteria, were identified together with other species such as Desulfovibrio, Pseudomonas, Arcobacter, Acinetobacter or Sulfurospirillum, which are usually found in cathodic biofilms. Moreover, results suggest that these communities are responsible of maintaining a stable reactor performance.