科研之友
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摘要
The mitochondrial states and activities of production yeasts used in the fermentation industry vary according to the availability of oxygen, size of the fermentation tank and temperature of the raw material. However, the involvement of the mitochondrial states of these yeasts in the production profile of organic acids during alcoholic fermentation has not been investigated in detail. In this study, the effects of the mitochondrial state of a sake brewing yeast on the organic acid production profile during an alcoholic fermentation process were investigated. It was elucidated that the mitochondrial state during the propagation stage significantly affected the mitochondrial morphology and the organic acid production profile during the alcoholic fermentation. When yeast mitochondria were active, they were highly branched in the propagation stage, and the yeast cells produced significantly more succinate and less malate. In contrast, when the yeast mitochondria were inactive, they were long and filamentous in appearance, and the yeast produced significantly less succinate and more malate. The change in malic acid content was reversed when an uncoupler of mitochondrial membrane potential, carbonylcyanide p-trifluoromethoxyphenylhydrazone, was added to the culture, indicating that the change in the organic acid production profile could be attributed to mitochondrial activity. Furthermore, the content of malic acid and succinic acid could be converted from a respirative to a fermentative profile by exposing the yeast to a mitochondrion-inactivating environment for 12 or 24 h. Taken together, it was shown that the mitochondrial status of the yeast affects malic acid production during alcoholic fermentation.
- 出版日期2012
