Temperature has a great influence on fermentation. It will affect the rate of various enzyme reactions, change the synthesis direction of bacterial metabolites, affect the metabolic regulation mechanism of microorganisms, affect the physical and chemical properties of fermentation broth, and then affect the dynamic characteristics of fermentation and the biosynthesis of products. The influence of temperature on the chemical reaction rate is usually expressed by the temperature coefficient (Q10) (the multiple of the chemical reaction rate when the temperature increases by 10 ℃).