目的:酵母相互作用在葡萄酒化学特征的定义中起着关键作用。出于这个原因,酿酒师对混合发酵越来越感兴趣,采用酿酒酵母和非酵母属菌株。然而,混合发酵的结果通常是矛盾的,因为物种内部的菌株之间存在很大的差异。以前,已证明,在与酿酒酵母的混合发酵中,杆菌属的可培养性丧失是由于细胞之间的物理接触。因此,为了进一步探索以前的观察,不同菌株之间的相互作用机制。研究了混合发酵过程中的芽孢杆菌和酿酒酵母。
结果:发酵在允许细胞(烧瓶)之间物理接触的条件下进行,但也使用双室发酵系统,其中两种物种的细胞保持分离。还研究了营养竞争和抗微生物化合物生产对酵母-酵母相互作用机制的作用。三Starm使用芽孢杆菌和三种酿酒酵母菌株来研究是否以菌株特异性方式调节相互作用机制。两个物种种群都受到身体接触的影响,尤其是Starm。在发酵过程中失去可培养性的杆菌。此外,Starm的可培养性丧失。在烧瓶中观察到的杆菌菌株比在双室系统中更早。观察到的现象以应变对依赖的方式发生。Starm.杆菌消失似乎与营养消耗或抑制性化合物的存在无关(本研究中未对其进行测量)。
结论:总体而言,本研究的结果表明,细胞与细胞的接触在非酵母属的早期死亡中起作用,但观察到的程度在很大程度上取决于Starm。芽孢杆菌/测试的酿酒酵母菌株。
OBJECTIVE: Yeast interactions have a key role in the definition of the chemical profile of the wines. For this reason, winemakers are increasingly interested in mixed fermentations, employing Saccharomyces cerevisiae and non-Saccharomyces strains. However, the outcome of mixed fermentations is often contradictory because there is a great variability among strains within species. Previously, it was demonstrated that the loss of culturability of Starmerella bacillaris in mixed fermentations with S. cerevisiae was due to the physical contact between cells. Therefore, to further explore previous observations, the interaction mechanisms among different strains of Starm. bacillaris and S. cerevisiae during mixed fermentations were investigated.
RESULTS: Fermentations were conducted under conditions that allow physical contact between cells (flasks) but also using a double-compartment fermentation system in which cells of both species were kept separate. The role of competition for nutrients and antimicrobial compounds production on yeast-yeast interaction mechanisms was also investigated. Three Starm. bacillaris and three S. cerevisiae strains were used to investigate if interaction mechanisms are modulated in a strain-specific way. Both species populations were affected by physical contact, particularly Starm. bacillaris that lost its culturability during fermentation. In addition, loss of culturability of Starm. bacillaris strains was observed earlier in flasks than in the double-compartment system. The phenomena observed occurred in a strain couple-dependent way. Starm. bacillaris disappearance seemed to be independent of nutrient depletion or the presence of inhibitory compounds (which were not measured in this study).
CONCLUSIONS: Overall, the results of the present study reveal that cell-to-cell contact plays a role in the early death of non-Saccharomyces but the extent to which it is observed depends greatly on the Starm. bacillaris/S. cerevisiae strains tested.