Abstract: In this study,ultrafiltration technique was used for purifying 5-hydroxytryptophan(5-HTP)from Griffonia simplicifolia. The results showed that the ultrafiltration membrane with cut-off molecular mass of 50K was better than these of 10K and 100 K in separating and purifying 5-HTP.In order to improve 5-HTP purity and transfer ratio,the optimal separation and purification conditions were investigated and obtained as follows:operating pressure was 0.10 MPa,the temperature was 35 ℃,the raw concentration of 5-HTP was 1.141 mg/mL,and the pH value was 7.0.Under the optimum conditions,the 5-HTP transfer ratio was 83.5%,and the purity of 5-HTP was 90.5%.

Key words: ultrafiltration, Griffonia simplicifolia, 5-hydroxytryptophan