混合培养条件下酵母菌菌株生长影响因素的初步研究

A Primary Study on the Factors Affecting Yeast Growth in a Mixed Culture

摘要:

为研究两种酵母菌在混合培养条件下各菌株生长相互影响的因素，本文考察了初糖浓度及pH对两种酵母菌Saccharomyces cerevisiae（简称Sc）和Issatchenkio orientalis（简称Io）生长的影响，以纯培养作对比，研究了混合培养条件下两种酵母菌有机酸代谢的差异性。结果表明，低糖浓度、低pH以及有机酸代谢的差异是造成混合培养条件下Sc生长受到抑制的主要因素；Io代谢葡萄糖速率较Sc快，在初糖浓度为1%的混合培养中，Io优先竞争性地消耗葡萄糖，混合培养体系中Io/Sc（菌落数量比值）为70；Io较Sc耐酸，在pH3.5下，Io/Sc达56；有机酸代谢中，Io可特异性地生成2.52 g/L的乳酸，Sc可特异性地生成1.14 g/L的乙酸，混合培养中，Io可吸收代谢Sc产生的乙酸，而Io产生的乳酸则对Sc的生长产生抑制作用。从细胞生长与有机酸代谢角度分析果酒酵母菌混合培养细胞行为影响的因素，为多菌种混合发酵在果酒产业中的应用提供理论基础。

Abstract:

To investigate the factors affecting the growth of different yeast strains in a mixed culture, the effects of initial glucose concentration and pH value on the growth of Saccharomyces cerevisiae (Sc) and Issatchenkia orientalis (Io) were investigated. The differences in organic acid metabolism of the two types of yeasts in a mixed culture were compared using pure cultures as controls. The results showed that low initial glucose concentration, low pH, and differences in organic acid metabolism were the main factors inhibiting the growth of Sc. The glucose consumption rate of Io was faster than that of Sc; in the mixed culture with an initial glucose concentration of 1%, Io consumed glucose preferentially, and the Io/Sc (the ratio of colony numbers) value was 70. Io was more acid tolerant than Sc, and the Io/Sc was 56 in pH 3.5. Regarding organic acid metabolism, Io produced 2.52 g/L lactic acid specifically, and Sc produced 1.14 g/L acetic acid specifically. In a mixed culture, Io could absorb the acetic acid produced by Sc, whereas the lactic acid produced by Io could inhibit the growth of Sc. The factors influencing cell behavior of wine yeasts in a mixed culture were analyzed in terms of cell growth and organic acid metabolism, and this study provides a theoretical basis for the application of multi-strain mixed fermentation in the wine industry.