Abstract:

The effect of tie line length (TLL) of ethanol-(NH4)2SO4 aqueous two phase system (ATPS) on the extraction
of polysaccharides from Porphyra haitanensis was investigated. The phase diagram was obtained by cloud point titration,
and then different TLLs of ATPS were selected and partition coefficients of polysaccharides were detected. The yield
and partition coefficient of polysaccharides were 79.8% and 0.23, respectively, using a system consisting of 27% ethanol
and 18% (NH4)2SO4 (forming a TLL of 40) with a top/bottom phase volume ratio of 1.1. The removal rate of protein was
significantly higher than that reported with traditional ethanol precipitation method (1.20% vs 6.17%). Meanwhile, the
proposed method had good decolorization effect. Thus, it can be used for the separation and purification of polysaccharides
from Porphyra haitanensis.

Key words: aqueous two-phase system, tie line length (TLL), Porphyra haitanensis, polysaccharides