Yeasts undergo intensive metabolic changes during the early stages of fermentation. Previous reports suggest the early production of hydrogen sulfide (H2S) is associated with the release of a range of volatile sulfur compounds (VSCs), as well as the production of varietal thiol compounds 3-sulfanylhexan-1-ol (3SH) and 3-sulfanylhexyl acetate (3SHA) from six-carbon precursors including (E)-hex-2-enal. In this study, we investigated the early H2S potential, VSCs/thiol output, and precursor metabolism of 11 commonly used laboratory and commercial Saccharomyces cerevisiae strains in chemically defined synthetic grape medium (SGM) within 12 hours after inoculation. Considerable variability in early H2S potential was observed among the strains surveyed. Chemical profiling suggested that early H2S production correlates with the production of dimethyl disulfide, 2-mercaptoethanol, and diethyl sulfide, but not with 3SH or 3SHA. All strains were capable of metabolizing (E)-hex-2-enal while the F15 strain showed significantly higher residue at 12 h. Early production of 3SH, but not 3SHA, can be detected in the presence of exogenous (E)-hex-2-enal and H2S. Therefore, the natural variability of early yeast H2S production contributes to the early output of selected VSCs, but the threshold of which is likely not high enough to contribute substantially to free varietal thiols in SGM.

中文翻译：

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早期酵母发酵过程中硫化氢的产生与挥发性硫化合物的生物发生有关，但与硫醇的释放无关

酵母在发酵的早期阶段经历强烈的代谢变化。先前的报告表明，硫化氢 (H2S) 的早期产生与一系列挥发性硫化合物 (VSC) 的释放以及各种硫醇化合物 3-硫烷基己-1-醇 (3SH) 和 3- 的产生有关。来自包括 (E)-hex-2-enal 在内的六碳前体的乙酸硫烷基己酯 (3SHA)。在本研究中，我们研究了 11 种常用实验室和商业酿酒酵母菌株在接种后 12 小时内在化学成分确定的合成葡萄培养基 (SGM) 中的早期 H2S 潜力、VSC/硫醇输出和前体代谢。在所调查的菌株中观察到早期 H2S 潜力存在相当大的差异。化学分析表明，早期 H2S 的产生与二甲基二硫醚、2-巯基乙醇和二乙硫醚的产生相关，但与 3SH 或 3SHA 无关。所有菌株均能够代谢 (E)-hex-2-enal，而 F15 菌株在 12 小时时显示出明显更高的残留量。在存在外源 (E)-hex-2-enal 和 H2S 的情况下，可以检测到 3SH 的早期产生，但不能检测到 3SHA。因此，早期酵母 H2S 产生的自然变异有助于选定 VSC 的早期输出，但其阈值可能不够高，不足以对 SGM 中的游离品种硫醇产生实质性贡献。