Institute for Biotechnology and Bioengeneering - Centre of Genomics and Biotechnology, Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal.
AMB Express. 2014 May 10;4:39. doi: 10.1186/s13568-014-0039-6. eCollection 2014.
Currently, pursuing yeast strains that display both a high potential fitness for alcoholic fermentation and a favorable impact on quality is a major goal in the alcoholic beverage industry. This considerable industrial interest has led to many studies characterizing the phenotypic and metabolic traits of commercial yeast populations. In this study, 20 Saccharomyces cerevisiae strains from different geographical origins exhibited high phenotypic diversity when their response to nine biotechnologically relevant conditions was examined. Next, the fermentation fitness and metabolic traits of eight selected strains with a unique phenotypic profile were evaluated in a high-sugar synthetic medium under two nitrogen regimes. Although the strains exhibited significant differences in nitrogen requirements and utilization rates, a direct relationship between nitrogen consumption, specific growth rate, cell biomass, cell viability, acetic acid and glycerol formation was only observed under high-nitrogen conditions. In contrast, the strains produced more succinic acid under the low-nitrogen regime, and a direct relationship with the final cell biomass was established. Glucose and fructose utilization patterns depended on both yeast strain and nitrogen availability. For low-nitrogen fermentation, three strains did not fully degrade the fructose. This study validates phenotypic and metabolic diversity among commercial wine yeasts and contributes new findings on the relationship between nitrogen availability, yeast cell growth and sugar utilization. We suggest that measuring nitrogen during the stationary growth phase is important because yeast cells fermentative activity is not exclusively related to population size, as previously assumed, but it is also related to the quantity of nitrogen consumed during this growth phase.
目前，在酒精饮料行业中，追求具有高酒精发酵潜力和对质量有有利影响的酵母菌株是一个主要目标。这种巨大的工业兴趣促使许多研究描述了商业酵母群体的表型和代谢特征。在这项研究中，20 株来自不同地理来源的酿酒酵母菌株在检测其对九种生物技术相关条件的反应时表现出高度的表型多样性。接下来，在两种氮源条件下，对具有独特表型特征的 8 株选定菌株在高糖合成培养基中的发酵适应性和代谢特性进行了评估。尽管这些菌株在氮需求和利用率方面表现出显著差异，但只有在高氮条件下，才观察到氮消耗、比生长速率、细胞生物量、细胞活力、乙酸和甘油形成之间的直接关系。相比之下，这些菌株在低氮条件下产生更多的琥珀酸，并且与最终细胞生物量建立了直接关系。葡萄糖和果糖的利用模式取决于酵母菌株和氮源的可用性。对于低氮发酵，有三株酵母菌株不能完全降解果糖。本研究验证了商业葡萄酒酵母之间的表型和代谢多样性，并为氮源可用性、酵母细胞生长和糖利用之间的关系提供了新的发现。我们建议在静止生长阶段测量氮，因为酵母细胞的发酵活性不仅与种群大小有关，如先前假设的那样，还与生长阶段消耗的氮量有关。
