The response surface optimization of exopolysaccharide produced by Saccharomyces cerevisiae Y3 and its partial characterization

Response surface methodology (RSM) was used to optimize the conditions of exopolysaccharides (EPSs) by Saccharomyces cerevisiae Y3. The results indicated that the yield of EPS reached 4.52 +/- 0.14 g/L with 10.30% (w/v) sucrose, 0.64% (w/v) yeast extract, liquid volume 141.5 mL, which was 2.40 times the original EPS yield. Y3 EPS contained 83.65 +/- 0.16% of total sugars, 15.27 +/- 0.26% of uronic acid, 0.78 +/- 0.02% of protein and 0.30 +/- 0.12% of sulfuric acid groups. Y3 EPS maintained a relatively low viscosity, with intrinsic viscosities of 306.58 mL/g (25 degrees C) and 200.91 mL/g (35 degrees C), respectively. The EPS had high water solubility index (WSI), high water holding capacity (WHC) and good emulsifying ability (EA). Meanwhile, the EPS could absorb metal ions such as Cu2+, Fe2+ and Zn2+. In addition, Y3 EPS exhibited good antioxidant properties and coagulated skim milk with a concentration-dependent manner. These results indicated that S. cerevisiae Y3 EPS had applicable prospects in medicine, food, especially the dairy industry.

Automated summary

The optimization of exopolysaccharides (EPSs) production by Saccharomyces cerevisiae Y3 using response surface methodology (RSM) yielded a significant increase in EPS yield and demonstrated favorable characteristics such as low viscosity, high water solubility, water holding capacity, emulsifying ability, as well as good antioxidant properties and metal ion absorption capabilities. Additionally, the EPS showed concentration-dependent coagulation effects on skim milk, indicating potential application in medicine, food, and particularly the dairy industry.