Conventional fermentation technology has known that can be adopted for production fermentation liquid containing ethanol with specific concentration by using yeast to apply a fermentation process to a specific raw material containing sugars, starches or fibers for 8-12 hours. However, an inadequate alcohol production per unit time becomes a principal drawback of the conventional fermentation technology. Accordingly, the present invention discloses a use of light source in stimulation of fermentation, wherein an illumination light provided by the light source has a color temperature in a range between 1600K and 4300K, and the illumination light is helpful in stimulating a biological fermentation occurring in an object under fermentation so as to enhance a rate of ethanol fermentation. Moreover, the present invention also discloses a device for stimulating biological fermentation, which can be applied in any one type of fermentation equipment. |