School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Institute of Applied Chemistry and Biological Engineering, Weifang Engineering Vocational College, 8979 Yunmenshan South Road, Qingzhou, Shandong 262500, China; Institute of Food Physical Processing, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
Ultrason Sonochem. 2019 Jun;54:39-47. doi: 10.1016/j.ultsonch.2019.02.017. Epub 2019 Feb 16.
In this study, the influences of ultrasonic treatments with different working modes (fixed frequency and sweeping frequency) and various frequencies on the bacterial growth and metabolism yield of Saccharomyces cerevisiae (S. cerevisiae) were investigated by employing an in situ ultrasonic irradiation slot coupled with a flask fermentation equipment. The results revealed that the in situ ultrasonic treatment could promote the bacterial growth and metabolism yield, and the effect of fixed frequency ultrasound (FF) was higher than sweeping frequency ultrasound (SF). The content of metabolite in the fermentation broth increased with FF and decreased after SF treatments. On the other hand, when the frequency of FF was more than 33 kHz, the growth of S. cerevisiae became weaken, and the mortality rate of S. cerevisiae increased in fermentation broth. At FF of 23 kHz and 48 h fermentation-time, ethanol content increased by 19.33%, and the content of β-phenylethanol and other volatile metabolites such as esters also increased. In conclusion, FF could significantly improve the growth of S. cerevisiae, and the FF of 23 kHz showed the optimum impact on fermentation process of S. cerevisiae.
本研究采用原位超声辐照槽与摇瓶发酵设备相结合的方式，考察了不同工作模式（固定频率和扫频）和不同频率的超声处理对酿酒酵母（Saccharomyces cerevisiae）细菌生长和代谢产物的影响。结果表明，原位超声处理能促进细菌生长和代谢产物的产生，固定频率超声（FF）的效果高于扫频超声（SF）。发酵液中代谢物的含量随 FF 增加而增加，随 SF 处理而减少。另一方面，当 FF 的频率超过 33 kHz 时，酿酒酵母的生长减弱，发酵液中酿酒酵母的死亡率增加。在 FF 为 23 kHz 和 48 h 发酵时间的条件下，乙醇含量增加了 19.33%，β-苯乙醇和其他挥发性代谢物如酯类的含量也增加了。总之，FF 能显著促进酿酒酵母的生长，FF 为 23 kHz 时对酿酒酵母发酵过程的影响最佳。
