The yeast TUM1 affects production of hydrogen sulfide from cysteine treatment during fermentation
The yeast TUM1 affects production of hydrogen sulfide from cysteine treatment during fermentation
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DOI：
10.1093/femsyr/fow100
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发表时间：
2016-12-01
影响因子：
3.2
通讯作者：
Jiranek, Vladimir
中科院分区：
文献类型：
--
作者：
Huang, Chien-Wei;Walker, Michelle E.;Jiranek, Vladimir
葡萄汁接种酵母后不久，酵母产生的令人不快的硫化氢（H2S）腐烂鸡蛋气味可能是理想的品种硫醇的重要来源，这有助于长相思等品种的热带香味。在这项研究中，我们观察到酿酒酵母菌株产生早期爆发的H2S从半胱氨酸。Delta met2和Delta met17菌株都产生更大的爆发，可能是因为它们无法在硫酸盐同化途径中利用H2S。这是第一次，我们表明，TUM1是部分负责早期生产H2S从半胱氨酸。过度表达TUM1增加了H2S的产生，而其缺失仅产生一半的H2S。我们通过分析缺乏转硫途径组分的突变体的生长，进一步证实了酵母将半胱氨酸转化为H2S。高浓度的半胱氨酸克服了这种生长阻滞，但需要TUM1。总体而言，数据表明S。酿酒酵母不将半胱氨酸转化为硫酸盐或亚硫酸盐，而是通过需要Tum1p作用的新途径转化为硫化物。这项研究的结果可能允许通过操纵硫代谢来改进商业酵母，使其更适合于生产水果驱动的风格。
The undesirable rotten-egg odour of hydrogen sulfide (H2S) produced by yeast shortly after yeast inoculation of grape musts might be an important source of desirable varietal thiols, which contribute to tropical aromas in varieties such as Sauvignon Blanc. In this study, we observed that Saccharomyces cerevisiae strains produce an early burst of H2S from cysteine. Both Delta met2 and Delta met17 strains produce a larger burst, likely because they are unable to utilise the H2S in the sulfate assimilation pathway. For the first time, we show that TUM1 is partly responsible for the early production of H2S from cysteine. Overexpressing TUM1 elevated production of H2S, whilst its deletion yields only half of the H2S. We further confirmed that yeast convert cysteine to H2S by analysing growth of mutants lacking components of the transsulfuration pathway. High concentrations of cysteine overcame this growth block, but required TUM1. Collectively, the data indicate that S. cerevisiae does not convert cysteine to sulfate or sulfite, but rather to sulfide via a novel pathway that requires the action of Tum1p. The findings of this study may allow the improvement of commercial yeasts through the manipulation of sulfur metabolism that are better suited towards production of fruit-driven styles.