Experimental and computational study of a packed-bed bioreactor for the continuous production of succinic acid

In this work we present a packed-bed bioreactor system packed, with immobilised cells in sodium alginate beads, for the biological conversion of glycerol to succinic acid. We simulate this continuous bioreactor system by constructing a partial differential equation, multi-phase, convection-diffusion model, which uses the intrinsic kinetics for the fermentation of glycerol with A. succinogenes. The model is validated by conducting a series of fermentation experiments at different operating conditions and is subsequently used to successfully predict the dynamics and the species profiles throughout the length of the bioreactor. The model is then exploited for optimising the continuous bioprocess. The computed optimal conditions are experimentally validated. The succinic acid concentration at the end effluent of the bioreactor reached 51.16 g L ⁻¹, with the substrate being fully consumed. The maximum succinic acid productivity was calculated to be 2.15 g L ⁻¹ h ⁻¹, a value which is the highest recorded for the bioproduction of succinic acid with glycerol.