Biodiesel production from catalytic transesterification of waste cooking oil (WCO) was investigated in a magnetically fluidized bed reactor (MFBR) over Pseudomonas mendocina cells immobilized in magnetic microspheres. The effects of methanol to oil molar ratio (MOMR), magnetic field intensity, biocatalysts concentration and reactant flow rate on biodiesel production were investigated. Optimization of the selected parameters was carried out for maximum biodiesel production using response surface methodology with support of Design-Expert software. The parameters optimized with response surface methodology were MOMR of 3.74:1, magnetic field intensity of 136.63 Oe, biocatalysts concentration of 10.21 wt. % and reactant flow rate of 16.97 mL/min. An experimental biodiesel yield of 91.8% was obtained at 35 degrees C after 48 h with these optimized parameters. Moreover, the magnetic whole-cell biocatalysts (MWCBs) exhibited good reusability in MFBR that 87.5% biodiesel yield could still be achieved after 10 cycles. The results suggested that MWCBs catalyzed transesterification in the MFBR system would have broad application prospects in biodiesel production. (C) 2017 Elsevier Ltd. All rights reserved.