The industrial adoption of microbial electrosynthesis (MES) is hindered by high overpotentials deriving from low electrolyte conductivity and inefficient cell designs. In this study, a mixed microbial consortium originating from an anaerobic digester operated under saline conditions (∼13 g L⁻¹ NaCl) was adapted for acetate production from bicarbonate in galvanostatic (0.25 mA cm⁻²) H-type cells at 5, 10, 15, or 20 g L⁻¹ NaCl concentration. The acetogenic communities were successfully enriched only at 5 and 10 g L⁻¹ NaCl, revealing an inhibitory threshold of about 6 g L⁻¹ Na⁺. The enriched planktonic communities were then used as inoculum for 3D printed, three-chamber cells equipped with a gas diffusion biocathode. The cells were fed with CO₂ gas and operated galvanostatically (0.25 or 1.00 mA cm⁻²). The highest production rate of 55.4 g m⁻² d⁻¹ (0.89 g L⁻¹ d⁻¹), with 82.4% Coulombic efficiency, was obtained at 5 g L⁻¹ NaCl concentration and 1 mA cm⁻² applied current, achieving an average acetate production of 44.7 kg MWh⁻¹. Scanning electron microscopy and 16S rRNA sequencing analysis confirmed the formation of a cathodic biofilm dominated by Acetobacterium sp. Finally, three 3D printed cells were hydraulically connected in series to simulate an MES stack, achieving three-fold production rates than with the single cell at 0.25 mA cm⁻². This confirms that three-chamber MES cells are an efficient and scalable technology for CO₂ bio-electro recycling to acetate and that moderate saline conditions (5 g L⁻¹ NaCl) can help reduce their power demand while preserving the activity of acetogens.