Ultrafiltration and nanofiltration membrane separation technology in extracting and purifying oligosaccharides of Rehmannia glutinosa / 中草药

ABSTRACT

Objective Oligosaccharides of Rehmannia glutinosa were separated and purified by different molecular weight cut-off ultrafiltration(UF) membranes,and then ultrafiltrate was concentrated and purified by nanofiltration(NF) membrane.Methods Different molecular weight cut-off UF unit first and then NF unit were used in process.Results Oligosaccharides were separated by twice UF,the optimum separation conditionsthe concentration of feed solution was 13—132 mg/mL,the operation pressure was 0.25—0.275 MPa,and the temperature was 20—40 ℃.Then ultrafiltrate was concentrated and purified by NF membrane,the optimum separation conditionsthe operation pressure was 0.59—0.79 MPa,the temperature was 20—40 ℃,and the concentration multiplegot to three.Under this condition,the total extraction rate of oligosaccharide products was 46.63% and the purity was above 93.3%,the molecular weights of oligosaccharide products determined by gel filtration were less than 6 000.Conclusion The technology is not only simple and feasible but also easy to separate and purify the oligosaccharides of R.glutinosa effectively.