Coenzyme Q10 production in a 150-l reactor by a mutant strain of Rhodobacter sphaeroides

For the commercial production of CoQ₁₀, batch-type fermentations were attempted in a 150-l fermenter using a mutant strain of R. sphaeroides. Optimum temperature and initial aeration rate were found to be 30°C and 2 vvm, respectively. Under optimum fermentation conditions, the maximum value of specific CoQ₁₀ content was achieved reproducibly as 6.34 mg/g DCW after 24 h, with 3.02 g/l of DCW. During the fermentation, aeration shift (from the adequate aeration at the early growth phase to the limited aeration in active cellular metabolism) was a key factor in CoQ₁₀ production for scale-up. A higher value of the specific CoQ₁₀ content (8.12 mg/g DCW) was achieved in fed-batch fermentation and comparable to those produced by the pilot-scale fed-batch fermentations of A. tumefaciens, which indicated that the mutant strain of R. sphaeroides used in this study was a potential high CoQ₁₀ producer. This is the first detailed study to demonstrate a pilot-scale production of CoQ₁₀ using a mutant strain of R. sphaeroides.