Volatile aroma compound production is affected by growth rate in S. cerevisiae
Volatile aroma compound production is affected by growth rate in S. cerevisiae
复制标题
挥发性香气化合物的产生受酿酒酵母生长速率的影响
DOI：
10.1101/2022.09.01.506294
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Visinoni F
中科院分区：
文献类型：
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作者：
Visinoni F
酵母菌的初始生长速度是发酵饮料生产中的一个关键参数。快速生长与较高的发酵能力有关，并导致发酵速度较慢，无法达到预期的最终重力。由于代谢物的浓度处于恒定的助熔剂状态，有关生长速度如何影响芳香化合物生产的定量数据成为酿酒商的重要因素。恒化器允许在整个发酵过程中设定并保持特定的稀释率，是研究生长对香气生产影响的理想系统。在这项研究中，我们在分批和补料分批培养的同时使用化学药物，比较在不同生长速度下检测到的挥发性成分，并确定那些受不同补料成分影响的成分。具体地说，我们量化了在不同稀释率下厌氧葡萄糖限制的酿酒酵母连续培养产生的六种丰富的香气化合物。我们发现，挥发性物质的产生受到所测试的六种化合物中四种的增长速度的影响，而高级醇和酯的趋势则相反。设计了分批和补料分批发酵，以研究挥发性化合物的最终浓度受葡萄糖可用性影响的程度。与分批发酵相比，补料分批发酵可显著提高高级醇的浓度，这与连续发酵的结果相一致。这项研究为发酵饮料生产的进一步工艺开发优化铺平了道路。重要的是，发酵饮料的生产将需要快速适应气候和客户需求的变化，需要开发新的菌株和工艺。由于对酵母菌的生理学和香气化合物生产之间相互作用的认识有限，阻碍了该领域的突破。在文献中没有关于生长速度如何影响香气特征的定量数据来指导发酵饮料中复杂风味的优化。在这项研究中，我们利用恒化器系统，以及分批和补料分批培养，比较不同生长速度下的挥发性分布。我们确定了不同摄食方式和营养限制对芳香族化合物的影响。此外，我们还发现了酵母生长、酯和高级醇生产之间的关系。这项研究展示了进料曲线在工艺饮料行业中应用于香气处理的潜力。
The initial growth rate of a yeast strain is a key parameter in the production of fermented beverages. Fast growth is linked with higher fermentative capacity and results in less slow and stuck fermentations unable to reach the expected final gravity. As concentrations of metabolites are in a constant state of flux, quantitative data on how growth rate affects the production of aromatic compounds becomes an important factor for brewers. Chemostats allow to set and keep a specific dilution rate throughout the fermentation and are ideal system to study the effect of growth on aroma production. In this study, we ran chemostats alongside batch and fed-batch cultures, compared volatile profiles detected at different growth rates, and identified those affected by the different feeding profiles. Specifically, we quantified six abundant aroma compounds produced in anaerobic glucose-limited continuous cultivations of S. cerevisiae at different dilution rates. We found that volatile production was affected by the growth rate in four out of six compounds assayed, with higher alcohols and esters following opposite trends. Batch and fed-batch fermentations were devised to study the extent by which the final concentration of volatile compounds is influenced by glucose availability. Compared with the batch system, fed-batch fermentations, where the yeast growth was artificially limited by a slow constant release of nutrients in the media, resulted in a significant increase in concentration of higher alcohols, mirroring the results obtained in continuous fermentations. This study paves the way to further process development optimization for the production of fermented beverages.IMPORTANCEThe production of fermentation beverages will need to quickly adapt to changes in both the climate and customer demands, requiring the development of new strains and processes. Breakthroughs in the field are hindered by the limited knowledge on the interplay between physiology and aroma compound production in yeast. No quantitative data on how growth rate affects aroma profile is available in the literature to guide optimization of the complex flavors in fermented beverages. In this study, we exploited the chemostat system, alongside with batch and fed-batch cultures, to compare volatile profiles at different growth rates. We identified the aromatic compounds affected by the different feeding profiles and nutrient limitations. Moreover, we uncovered the correlation between yeast growth, esters, and higher alcohols production. This study showcases the potential of the application of feeding profiles for the manipulation of aroma in the craft beverage industry.