酿酒酵母细胞表面电位与絮凝相关性分析
Correlation between surface potential and flocculation of Saccharomyces cerevisiae
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摘要: 为探究酿酒酵母细胞表面所带电荷与絮凝的相关性,以两种液态发酵酵母和两种固态发酵酵母为研究对象,并对液态发酵酵母FFC2144和固态发酵酵母L2Y进行连续传代培养,用zeta电位仪测定其zeta电位,以细胞沉降速率的方法考察酵母的絮凝性。结果显示,离子强度为0时,固态发酵酵母zeta电位(绝对值)均小于30 m V,液态发酵酵母均大于30 m V,培养72 h后的固态发酵酵母絮凝率达到了80.2%,液态发酵酵母絮凝率最大仅为14.4%。在发酵过程中不同酿酒酵母电位无明显变化。随着传代次数的增加酿酒酵母FFC2144 zeta电位无明显变化,絮凝性能却逐渐增强,到第20代时絮凝率达到了94.8%。不同酿酒酵母具有不同的zeta电位,其大小客观地反映出酿酒酵母絮凝性的强弱。酿酒酵母在衰老过程中细胞的絮凝性与zeta电位无关。Abstract: Two liquid fermentating yeasts and two solid fermentating yeasts were prepared for the research to study the relevance between surface potential and flocculation of Saccharomyces cerevisiae. Saccharomyces cerevisiae FFC144 and L2 Y were inoculated from generation to generation,zeta potentials of different breed yeasts and different generation were measured using a standard instrument,yeast flocculability was measured by the method of calculating cells sedimentation rate. Results showed that,when ionic strength was 0,zeta potential of solid fermentating yeasts were less than 30 m V(absolute value),while the liquid fermentating yeasts in all cases were more than 30 m V,the flocculation rate of the solid fermentating yeasts which were cultivated72 h reached 80.2%,and the liquid fermentating yeasts possessed a maximum value of only 14.4%. There was no significant alteration of the zeta potential in the process of fermentation,and so was the Saccharomyces cerevisiae FFC2144 in the process of subculturing. Flocculability of the Saccharomyces cerevisiae FFC2144 was enhanced gradually which reached 94.8% in the 20 th generation. Different Saccharomyces cerevisiae possessed different zeta potential,the magnitude of which objectively reflected the strength of flocculability. In the process of yeast aging,flocculation had nothing to do with the surface potential of cells.