Department of Wine & Food Science, University of Adelaide, Glen Osmond, South Australia 5064, Australia; Australian Research Council Industrial Transformation Training Centre for Innovative Wine Production, Glen Osmond, South Australia 5064, Australia.
Department of Wine & Food Science, University of Adelaide, Glen Osmond, South Australia 5064, Australia.
Int J Food Microbiol. 2019 Apr 2;294:42-49. doi: 10.1016/j.ijfoodmicro.2019.01.014. Epub 2019 Feb 2.
Wine fermentations typically involve the yeast Saccharomyces cerevisiae. However, many other yeast species participate to the fermentation process, some with interesting oenological traits. In this study the species Torulaspora delbrueckii, used occasionally in mixed or sequential fermentation with S. cerevisiae to improve wine sensory profile, was investigated to understand the physiological differences between the two. Next generation sequencing was used to characterize the transcriptome of T. delbrueckii and highlight the different genomic response of these yeasts during growth under wine-like conditions. Of particular interest were the basic differences in the glucose fermentation pathway and the formation of aromatic and flavour compounds such as glycerol, esters and acetic acid. Paralog genes were missing in glycolysis and glycerol biosynthesis in T. delbrueckii. Results indicate the tendency of T. delbrueckii to produce less acetic acid relied on a higher expression of alcoholic fermentation related genes, whereas acetate esters were influenced by the absence of esterases, ATF1-2. Additionally, in the Δbap2 S. cerevisiae strain, the final concentration of short branched chain ethyl esters (SBCEEs) was related to branched chain amino acid (BCAA) uptake. In conclusion, different adaption strategies are apparent for T. delbrueckii and S. cerevisiae yeasts, an understanding of which will allow winemakers to make better use of such microbial tools to achieve a desired wine sensory outcome.
葡萄酒发酵通常涉及酵母酿酒酵母。然而，许多其他酵母物种也参与发酵过程，其中一些具有有趣的酿造特性。在这项研究中，偶尔会与酿酒酵母混合或顺序发酵以改善葡萄酒感官特征的毕赤酵母属被用来研究这两种酵母之间的生理差异。下一代测序用于表征毕赤酵母属的转录组，并强调了这两种酵母在葡萄酒样条件下生长时不同的基因组反应。特别有趣的是葡萄糖发酵途径和形成芳香和风味化合物如甘油、酯和乙酸的基本差异。毕赤酵母属的糖酵解和甘油生物合成中缺少同工基因。结果表明，毕赤酵母属产生较少乙酸的趋势依赖于与酒精发酵相关基因的更高表达，而乙酸酯则受酯酶 ATF1-2 缺失的影响。此外，在Δ bap2 酿酒酵母菌株中，短支链乙基酯（SBCEEs）的最终浓度与支链氨基酸（BCAA）的摄取有关。总之，毕赤酵母属和酿酒酵母属的适应策略明显不同，了解这些策略将使酿酒师能够更好地利用这些微生物工具来实现预期的葡萄酒感官效果。
