This work investigates the bioproduction of 1,3-propanediol (1,3-PD) from biodiesel derived raw glycerol with free and immobilized cells of Clostridium butyricum DSMZ 10702. The cultures were carried out under continuous conditions in a stirred tank bioreactor with suspended cells and a fluidized-bed bioreactor with immobilized cells. The microorganisms were immobilized by entrapment in calcium alginate gel beads. The effect of dilution rate and glycerol concentration in the feed on 1,3-PD production was investigated for both bioreactor configurations. Results showed that 1,3-PD concentration and glycerol uptake decreased when dilution rate increased. Maximum product concentration was similar in both bioreactors, 24.3 g/L and 20.5 g/L for suspended cells and Ca-alginate immobilized cells, respectively, for a glycerol feed concentration of 50 g/L and a dilution rate of 0.05 h(-1). The higher productivities were observed for a dilution rate of 0.15 h(-1) for the suspended culture bioreactor and 0.2 h(-1) for the immobilized cell bioreactor. Although maximum productivity was similar in both systems, 2.8 g 1,3- PD/(L . h), cell immobilization was shown to be more resistant to washout at higher dilution rates.