Stimulation of beta-glucan production from Saccharomyces carlsbergensis RU01 by tannin

Abstract

This study aimed to evaluate the tannin-stimulated production of β-glucan from Saccharomyces carlsbergensis RU01 in molasses medium. Central composite design was used for the experiment design. The optimum concentrations of molasses (X1), ammonium sulfate (X2), and tannin (X3), which produced the highest biomass, were determined. Optimization analysis revealed that the optimum concentration of substrates for biomass was 3% (w/v) of molasses, 0.1% (w/v) of ammonium sulfate and 0.1% (w/v) of tannin. The maximum biomass production was 2.64 g/L. Meanwhile, the experimental validation was 2.84±0.10 g/L, and the highest β-glucan production was 119.47 mg/g of dry cell weight. Carbohydrate content in yeast cell walls was detected by Congo red staining. The cell wall of yeast grown in the optimized medium with tannin showed higher intensity than that grown in yeast malt medium. These results suggested that tannin addition can enhance β-glucan production with a high β-1,3-glucans content in the cell wall of S. carlsbergensis RU01.