[论文解读] Electro-stimulation of S. cerevisiae wine yeasts by pulsed electric field and its effects on fermentation capacity

Jessy Mattar, Mohammad Turk+4 more|arXiv (Cornell University)|Apr 21, 2013

Microbial Inactivation Methods参考文献 33被引用 2

一句话总结

本研究探讨了脉冲电场（PEF）电刺激酿酒酵母（*S. cerevisiae*）以提升发酵性能。在100和6000 V/cm的PEF处理下，糖分消耗在滞留期显著加快，发酵效率提高，其中6000 V/cm处理使果糖消耗量提高3.98倍，质量损失时间相比对照组缩短20小时。

ABSTRACT

The batch fermentation process, inoculated by pulsed electric field (PEF) treated wine yeasts (S. cerevisiae Actiflore F33), was studied. PEF treatment was applied to the aqueous yeast suspensions (0.12 % wt.) at the electric field strengths of E=100 and 6000 V/cm using the same pulse protocol (number of pulses of n=1000, pulse duration of ti=100 mks, and pulse repetition time of dt=100 ms). Electro-stimulation was confirmed by the observed growth of electrical conductivity of suspensions. The fermentation was running at 30°C for 150 hours in an incubator with synchronic agitation. The obtained results clearly evidence the positive impact of PEF treatment on the batch fermentation process. Electro-stimulation resulted in improvement of such process characteristics as mass losses, consumption of soluble matter content (°Brix) and synthesis of proteins. It also resulted in a noticeable acceleration of consumption of sugars at the initial stage of fermentation in the lag phase. At the end of the lag phase (t=40 hours), consumption of fructose in samples with electrically activated inocula exceeded fructose consumption in samples with control inocula by 2.33 times when it was activated at E=100 V/cm and by 3.98 times after treatment at E=6000 V/cm. At the end of the log phase (120 hours of fermentation), 30% mass reduction was reached in samples with PEF-treated inocula (E=6000 V/cm), whereas the same mass reduction of the control sample required approximately, 20 hours of extra fermentation. The possible mechanisms of electro-stimulation are also discussed in details.

研究动机与目标

• 评估脉冲电场（PEF）处理对*S. cerevisiae*发酵能力的影响。
• 确定通过PEF实现电刺激是否能提升发酵动力学与效率。
• 确定能最大化发酵性能的最佳PEF参数（电场强度）。
• 探讨酵母细胞中电刺激作用的潜在机制。

提出的方法

• 在0.12% wt.浓度下对*S. cerevisiae*悬浮液施加脉冲电场（PEF）处理。
• 测试了两种电场强度：100 V/cm和6000 V/cm，脉冲数为1000次，脉冲宽度为100 µs，脉冲重复时间为100 ms。
• 在30°C下以批次模式进行发酵，持续150小时，并保持持续搅拌。
• 电导率变化证实了酵母悬浮液中电刺激效应的存在。
• 随时间监测发酵参数，包括质量损失、°Brix降低、蛋白质合成及糖分消耗。
• 对PEF处理组与对照组接种物进行对比分析，以评估性能提升情况。

实验结果

研究问题

• RQ1 PEF处理是否能增强*S. cerevisiae*葡萄酒酵母的发酵能力？
• RQ2 不同电场强度（100 V/cm与6000 V/cm）如何影响发酵动力学与糖分消耗速率？
• RQ3 与未处理对照组相比，电刺激在多大程度上缩短了发酵时间？
• RQ4 PEF处理后，质量损失与可溶性物质消耗的可测量改善程度如何？
• RQ5 PEF诱导的酵母细胞电刺激作用的潜在生理机制是什么？

主要发现

• 在40小时（滞留期末期），100 V/cm处理组的果糖消耗量是对照组的2.33倍。
• 在40小时，6000 V/cm处理组的果糖消耗量是对照组的3.98倍。
• 至120小时（对数生长期末期），6000 V/cm处理组的样品质量减少了30%，而对照组需额外20小时才能达到相同效果。
• PEF处理显著加速了初始滞留期的糖分消耗，表明代谢活性得到增强。
• 电导率测量结果证实了PEF暴露后酵母悬浮液中电刺激现象的发生。
• 本研究表明，PEF处理通过增强代谢活性和底物利用效率，提升了发酵效率。