1,3-Propanediol is one of the promising bulk chemicals,which has enormous application in solvents,antifreeze,lubricants,adhesives,foods,cosmetics,medicines and polymers [1].Recently the great progresses in microbial production of 1,3-propanediol have been received using renewable feedstocks.However,downstream processing is still the bottleneck for industrialization of 1,3-propanediol due to its low volatility,great affinity for water,and complexity of fermentation broth.Although considerable efforts have been made,including evaporation,distillation,membrane filtration,pervaporation,molecular sieves,chromatography,liquid–liquid extraction and reactive extraction,all these methods have some limitations [2].The appearance of salting-out extraction (SOE) as a novel and efficient separation technique for meeting the special need of concentration and purification of hydrophilic bio-based chemicalshas attracted increasing attention [3-6].In this study,the technical feasibility of continuous extraction of 1,3-propanediol from both simulated solution and filtrated fermentation broth in a experimental packed column was investigated using a salting-out extraction system of dipotassium phosphate/ethanol.Mass transfer of 1,3-propanediol takes place from the dispersed phase (salt-rich solution) to the continuous phase (ethanol).The influences of flow rate of dispersed phase and size of packing material on partition coefficient and recovery of 1,3-propanediol were investigated and the results were compared with those obtained in spray column and test tube.Furthermore,the influences of various system compositions on hold up of dispersed phase,mass transfer coefficient,and system stability were also studied.It has been shown that the size of packing material largely contributed to the extraction differences and the smaller packing of stainless steel Dixon 3×3mm was selected because of the high partition coefficient and recovery of 1,3-propanediol.The partition coefficient in a packed column decreased as the flow rate of dispersed phase increased,while the recovery increased slightly owing to bigger volume of extracted phase.The hold up of dispersed phase and mass transfer coefficient increased as flow rate of dispersed phase increased.At 1ml/min of flow rate of dispersed phase,90.30% of 1,3-propanediol in the real fermentation broth was extracted by the packed column in a continuous mode for 11 h,proving good repeatability and stability.Moreover,the phosphate recovery of 94.4% was achieved by adding 0.2 volume of ethanol into the raffinate phase at pH 4.0.The results above mentioned demonstrated the continuous salting-out extraction in the packed column had good extraction efficiency and stability,which has potential application prospect at a large scale level.