Biological methanation is a promising sustainable energy technology. To intensify ex-situ biomethanation, a 3-L bubble column reactor was operated continuously under thermophilic conditions, with and without colonized biochips. Studies in batch reactors showed biofilm formation on biochips, with an archaea:bacteria ratio of 5.7 compared to 3.2 in planktonic phase with Methanothermobacter being the dominant archaea. Using colonized biochips in the bubble column increased methane production rate (MPR) nearly threefold, achieving a steady MPR of 15.7 ± 0.5 NLCH4/Lr.d at 84.4 ± 0.9 % methane content. Gas retention time (GRT) was 0.3 h, with 97.4 % and 96.5 % conversion of H2 and CO2, respectively. Volatile fatty acid (VFA) production was under 40 mg/L per day, indicating dominant hydrogenotrophic methanogenic (HM) pathway. The results suggest biofilm formation significantly enhances MPR in ex-situ methanation reactors, advancing towards industrial application.