The Production Of Coenzyme Q₁₀ By Microbial Fermentation

Being an electron transfer component in the respiratory chain of living organisms, Coenzyme Q₁₀has been widely used in many fields, such as biomedicine, cosmetics, nutriment and so on. Coenzyme Q₁₀ produced by microbial fermentation has the advantages of high product activation and low raw material cost. At present, It is attracted much more interests to research.Coenzyme Q₁₀-producing strain CG was screened out from strains which were kept in our laboratory. Through treatment by Co⁶⁰-γray, microwave, UV, LiCl and rational screening with precursor resistant and kanamycin resistant. An over-production mutant PN251 was obtained from its parent strain CG The biomass for this mutant by shake culture was 6.21g/L and the productivity of Coenzyme Q₁₀ was 11.2 mg/L, which was 255 % higher than the parent strain. After eight times of subculture, the production of coenzyme Q₁₀ for strain PN251 still kept 97.3 %. It was a potential strain for the production of coenzyme Q₁₀.Based on single factor experiments, Plackett-Burman experiments and the response surface analysis, the optimal compositions of fermentation medium were as follows: glucose 2.51%, peptone 0.53%, yeast extract 0.3 %, K₂HPO₄ 0.05%, KH₂PO₄ 0.03%, MgSO₄ 0.03%, PHB 0.226%, bean oil 3 %; The optimum culture conditions were as follows: inoculum size 10%, the initial pH of medium 6.0, culture temperature 30℃, 40 ml culture medium in 250 ml shaken flask and rotation rate 180 r/min. In optimum conditions, the production of coenzyme Q₁₀ could reach 35.5 mg/L, with an increase of 217% compared to parent conditions.Through the experiment in 5L bioreactor, it was found that the production of Coenzyme Q₁₀ reached 39.8 mg/L at the time of 40 h in batch fermentation. When feeding of bean oil with 10 ml/h at the time of 24 h- 33h, the production of Coenzyme Q₁₀ reached 48.7 mg/L, an increase of 22.3 % comparision to that without feeding. The fermentation time reached 52 h.