Abstract:Yeast β-glucan is a component of cell wall structural polysaccharide with various biological functions. However, the poor water solubility of natural yeast β-glucan has limited its application in medical, health food and cosmetic industries. The low molecule β-glucan was prepared to improve the solubility by degradation of yeast β-glucan using β-1,3-glucanase Gly5m and β-1,6-glucanase BT3312. Heterologous expression of β-1,3-glucanase Gly5m and β-1,6-glucanase BT3312 were expressed by Escherichia coli. After induced with 0.2 mmol/L IPTG at 25 ℃, the highest enzyme activities of Gly5m and BT3312 were 1 086 U/mL and 2 355 U/mL, respectively. The solubility of yeast β-glucan separately hydrolyzed by Gly5m or BT3312 increased by 2.6 or 2.4 times. The solubility of yeast β-glucan co-hydrolyzed by Gly5m and BT3312 increased by 3.2 times, and the concentration of water-soluble yeast glucan reached 12.5 g/L. Therefore, Gly5m and BT3312 have important application value in improving the water solubility of yeast glucan and preparing small molecule yeast glucan.
