Factors affecting broth viscosity and coenzyme Q10 production by Agrobacterium species

Summary In the production of coenzyme Q₁₀ (CoQ₁₀) by Agrobacterium sp. the culture broth becomes highly viscous. In an attempt to improve the production process, the effects of chemical and physical factors on broth viscosity and CoQ₁₀ production were studied, using Agrobacterium sp. KY-8593. A particular concentration ratio of sugar to ammonium-nitrogen (NH₄–N) in the medium could effectively enhance CoQ₁₀ production without increasing broth viscosity. An increase in culture temperature to between 32°C and 34°C lowered broth viscosity without reducing CoQ₁₀ production. NH₄–N concentration and temperature had a correlative effect on broth viscosity. At a temperature of about 33°C, there was a wide range of NH₄–N concentration which was optimal for both broth viscosity and CoQ₁₀ production. In optimal conditions with 8% sugar the apparent broth viscosity was reduced to less than 10 pseudo-cP and CoQ₁₀ production was increased to more than 80 mg/l.