Performances of different syngas fermentation reactors were compared during the production of hydrogen and methane using a mixed culture of R. rubrum, M. formicicum and M. barkeri. The TBR was reported to have better CH4 productivity, CO gas conversion and mass transfer capabilities than the packed bubble column reactor (PBR). The mass transfer coefficients of 3.5 h-1 and 780 h-1 were reported for PBR and TBR, respectively . The TBR showed better mass transfer capabilities than PBR and STR for the production of acetate from syngas by P. productus.