Separation of Chitooligosaccharides with Specific Degree of Polymerization by Membrane Separation Technology

In order to obtain chitooligosaccharides with specific degree of polymerization,separation conditions(feed concentration,temperature and TMP)of 1000 Da nanofiltration membrane were studied to find the effects of nanofiltration process in separation of COS mixture. And mathematic model was established to predict yield and purity of COS in continue diafiltration process. Results showed that:The best conditions of feed concentration,temperature and TMP were 70 g/L,45 ℃,15 bar,respectively. In the best operation conditions,DP 2~5 COS was obtained from COS mixture by continue diafiltration and concentration processes. The purity and yield of DP 2~5 COS were 82.1% and 42.1%,respectively. The purity and yield of DP 2~5 COS were predict successfully through mathematic model. This study provided a potential production process for the separation of COS with specific DP by nanofiltration,and provided basis for application research and applying development of COS.