Production of soluble β-glucan from the cell wall of Saccharomyces cerevisiae

β-Glucan is a major component of the yeast cell wall, and plays an important role in the immune system and skin protection. The composition and structure of the yeast cell wall vary with species. The yeast cell wall is also affected by the composition of media and the culture conditions. After cultivating Saccharomyces cerevisiae, the cell wall fraction was prepared by cell lysis using a homogenizer. The crude cell wall extracts were purified to the soluble β-glucan by ethanol precipitation followed by DEAE ion-exchange chromatography, ConA chromatography, and freeze-drying. In batch cultivation of S. cerevisiae, the soluble β-glucan content and the resistance of the cell wall to β-glucanase was highest at early stationary phase. In continuous cultivation of S. cerevisiae, the soluble β-glucan content and the resistance of cell wall to β-glucanase were higher at lower dilution rate. Based on the results obtained from batch and continuous cultivation of S. cerevisiae, fed-batch cultivation was chosen for the mass production of soluble β-glucan. When S. cerevisiae was grown on 1.5-fold concentrated Dw medium and 15 g of glucose 50 ml−1 solution was fed intermittently, 0.13 g β-glucan g−1 dried cell was obtained, and the productivity of β-glucan was 0.095 g β-glucan l−1 culture broth h−1.