Oxygen Uptake Rate Controlling Strategy Balanced with Oxygen Supply for Improving Coenzyme Q_(10) Production by Rhodobacter sphaeroides

摘要

The effects of different oxygen uptake rates (OUR) on the physiological metabolism of Rhodobacter sphaeroides were investigated systematically in 50 L fermenters due to the significant influence on industrial coenzyme Q_(10) production under oxygen supply limitation. Meanwhile, the seriously decreased oxygen transfer rate caused by the increased broth viscosity was successfully prevented with OUR-directed continuous ammonium sulfate feeding in the late fermentation phase. The statistical analysis results showed that controlling OUR constantly at 45 ± 2.2 mmol/L/h by the oxygen supply level adjustment and the continuous ammonium sulfate feeding could greatly enhance Q_(10) production. This OUR-Stat controlling strategy successfully achieved the maximal coenzyme Q_(10) production (2584 ± 82 mg/L), which was 15.4% higher than that of the control. The highest specific CoQ_(10) content was 25.9 mg/(g DCW)), and the yield of CoQ_(10) to glucose consumption was up to 19.37 mg/g. These results demonstrated that the optimal OUR-Stat controlling strategy would be effective and economical for improving the industrial CoQ_(10) production.