Application of ultrafiltration for improved productivity in continuous acetone-butanol fermentation

Abstract

Ultrafiltration was applied for improved productivity in continuous acetone-butanol fermentation. A multitubular ceramic ultrafilter with 0.203 m2 surface area was used to separate and recycle cells in a continuous fermentation of clostridium acetobutylicum ATCC 824. The optimum applied pressure and recirculation flow rate were 0.17 kg.cm-2 and 0.4 m3 hr-1 respectively. From the experiments of total cell recycle system with the glucose of concentration varing from 40 to 60 gl-1 and the dilution rate varing from 0.11 to 0.55 hr-1 , the maximal solvent productivity was achieved at 42.4 gl-1 of glucose concentration at a dilution rate of 0.55 hr-1. Under total cell recycle, a maximal solvent productivity was attained at about 6.06 gl-1hr-1. The product solution had a concentration of 11.03 g.l-1 and consisted the combination of 6.26 gl-1 butanol, 4.40 gl-1 acetone and 0.37 gl-1 ethanol. A dry weight concentration of 80 gl-1 was obtained with 19.30 gl-1hr-1 glucose consumption and 0.31 production yield.