This study used various biocarriers (e.g., porites corals, Biolite (TM), porous ceramic filter media (PCFM)) to immobilize cells in fixed bed bioreactor (FBB) for wastewater decolorization. As prior studies proposed, an innovative graphical method of constant-slope isoclines to determine maximal allowable treatment capacity (MATC) was used as screening criteria for feasibility of packing matrices of immobilized cell systems (ICSs). Moreover, detailed inspection upon physical and chemical characteristics of packing matrices was also carried out to confirm the consistency of MTAC. The result of isocline analysis was in parallel with physical characteristics of biocarriers (i.e., porites coral > Biolite (TM) > PCFM). This first-attempt study successfully provided perspective in general terms to assess how the selected supporting materials were suitable to be packing matrices of ICSs for industrial applications (e.g., wastewater treatment). (C) 2013 Elsevier Ltd. All rights reserved.