Abstract:

Yeast cell wall polysaccharide contains some groups that can combine metal ions for executing bioactive
functions such as immunity. Yeast polysaccharide-Zn complex was prepared in this study to explore the absorption
performance of urea and to extend the application of yeast polysaccharide. Yeast polysaccharide-Zn complex is composed
of yeast polysaccharide and zinc sulfate. The influential factors of complex preparation such as reaction time, zinc addition
amount, reaction temperature and reaction pH were investigated. The optimal conditions of zinc complex preparation were
explored by orthogonal tests using urea adsorption as the evaluation index. The results indicated that the optimal preparation
conditions of yeast polysaccharide-Zn complex required reaction temperature of 55 ℃, reaction time of 2 h, addition of 10%
of 0.1 mol/L zinc sulfate, and reaction pH of 6.5. Under the optimal reaction conditions, the binding rate was up to 98.97%.
The optimal adsorption conditions of yeast polysaccharide-Zn complex for urea were reaction temperature of 30 ℃, reaction
pH of 6.0, reaction time of 135 min and initial urea concentration of 2.25 mg/mL. Under these optimal conditions, the
adsorption rate was up to 97.27%. The higher binding rate between yeast polysaccharide and zinc ion can provide the better
adsorption for urea.

Key words: yeast polysaccharide, zinc ion, yeast polysaccharide-Zn, preparation, urea, adsorption