pH和Ca^(2+)协同作用对酵母代谢及细胞膜功能的影响

Synergetic Effects of pH and Ca^(2+) on Yeast Metabolism and Cell Membrane Function

为了探究不同pH下添加不同浓度的Ca^(2+)对酿酒酵母的代谢机制以及细胞膜功能的影响,以酿酒酵母为研究对象,利用模拟葡萄汁培养基,通过调整培养基中pH值和Ca^(2+)含量,研究了酵母菌的代谢特征,并从细胞膜通透性和完整性的角度考察酵母代谢的机制。在确定的发酵条件下进行发酵:温度为28℃、转速为120 r/min,接种量为1×10~6 mol/L。结果表明,当pH为3.0时,随着Ca^(2+)浓度的增加,酵母菌代谢速率加快,酵母菌细胞膜的通透性和完整性也增强,即Ca^(2+)的添加减弱低pH对酵母的抑制作用。而当pH为5.5时,Ca^(2+)对酵母菌代谢速率以及细胞膜的通透性和完整性作用不明显。结果表明Ca^(2+)能缓解低pH下酿酒酵母的生理毒害作用。

This work is to explore the metabolic mechanism of Saccharomyces cerevisiae and the change of the cell membrane functionwhile adding different concentrations of Ca^（2＋） under different pH. Using S. cerevisiae as research target,the metabolic characteristics of yeastcells were studied by adjusting pH and the concentration of Ca^（2＋） in model grape juice medium,and also the metabolic mechanisms wereinvestigated from the perspective of permeability and integrity of the cell membrane. The fermentation was conducted under the condition oftemperature was 28℃,rotation speed was 120 r/min,and inoculation was 1×10~6 mol/L. Results showed that the rate of metabolism wasaccelerated,and the permeability and integrity of cell membrane were enhanced with the increase of Ca^（2＋） concentration when the pH was 3.0,indicating that the inhibiting effect caused by low pH was eliminated after adding Ca^（2＋）. The effect of Ca^（2＋） addition was not significant when thepH was 5.5. The above results indicated that Ca^（2＋） alleviated the physiologically toxic effects of low pH on S. cerevisiae.