GOx/Fe3O4/TiO2 on natural kissiris support was produced by consecutive preparation of TiO2/kissiris and Fe3O4/TiO2/kissiris followed by immobilization of Glucose Oxidize (GOx). This magnetic biocatalyst was used for continuous elimination of Malachite Green (MG) from aqueous solution in a packed bed reactor through bio-Fenton reaction. The biocatalyst was characterized by FT-IR, EDX and SEM analyses. Residence time distribution (RTD) of MG in the reactor was measured and parameters of the Langmuir-Hinshelwood kinetics model were obtained for the decolorization process. Hydrodynamics of the packed bed reactor were investigated via a thorough computational fluid dynamics (CFD) simulation using Eulerian approach in axisymmetric space and results were validated using experimental RTD curves and decolorization efficiencies. Ultimately, process simulation was utilized to obtain design parameters of the packed bed reactor in recirculating mode with 99.1% decolorization efficiency. The knowledge obtained through this study can be used to design and scale-up continuous and efficient bioreactors for treatment of wastewater. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.