This research aimed to assess how the partial removal of carbon dioxide affects fermentations to provide a better understanding of how the manipulation of carbon dioxide concentration can be used to optimize industrial fermentations. To achieve this, fermentation kinetics, fermentation metabolic products, and yeast stress indicators were analyzed throughout ongoing brewing fermentations conducted under partial vacuum with atmospheric pressure controls. The partial vacuum reduced the solubility of carbon dioxide in the media and decreased the time necessary to reach carbon dioxide saturation. The effect was an increased rate of fermentation, and significantly more viable cells produced under vacuum pressure compared to controls. Ethanol, glycerol, and volatile organic compound concentrations were all significantly increased under partial vacuum while indicators of yeast stress (trehalose) were reduced Additionally, as the number of yeast cells were higher under partial vacuum, less sugar was consumed per volume of yeast cell. This study measured fermentation kinetics, metabolic products, and yeast health to holistically assess the effect of partial vacuum during a batch fermentation and found significant differences in each that can be individually exploited by researchers and industry. Summary An exploration of batch yeast fermentation in a low-pressure environment, with a focus on the health and productivity of the yeast cells.

中文翻译：

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CO2 浓度对酵母发酵的影响：速率、代谢产物和酵母应激指标

这项研究旨在评估部分去除二氧化碳如何影响发酵，以便更好地了解如何利用二氧化碳浓度的操纵来优化工业发酵。为了实现这一目标，在大气压力控制的部分真空下进行的整个酿造发酵过程中，对发酵动力学、发酵代谢产物和酵母应激指标进行了分析。部分真空降低了二氧化碳在介质中的溶解度并减少了达到二氧化碳饱和所需的时间。其效果是发酵速率增加，并且与对照相比，在真空压力下产生的活细胞明显更多。乙醇、甘油和挥发性有机化合物的浓度在部分真空下均显着增加，而酵母应激指标（海藻糖）则降低。此外，由于部分真空下酵母细胞的数量较多，单位体积酵母细胞消耗的糖量较少。这项研究测量了发酵动力学、代谢产物和酵母健康状况，以全面评估分批发酵过程中部分真空的影响，并发现每一项都存在显着差异，可供研究人员和行业单独利用。摘要 探索低压环境下的批量酵母发酵，重点关注酵母细胞的健康和生产力。