Precise regulating the specific oxygen consumption rate to strengthen the CoQ10 biosynthesis by Rhodobater sphaeroides

Abstract Coenzyme Q 10 (CoQ 10 ) is the most consumed dietary supplement and mainly biosynthesized by aerobic fermentation of Rhodobacter sphaeroides ( R. sphaeroides ). Oxygen supply was identified as a bottleneck for improving CoQ 10 yield in R. sphaeroides . In this study, a precise regulation strategy based on dielectric spectroscopy (DS) was applied to further improve CoQ 10 biosynthesis by R. sphaeroide . First, a quantitative response model among viable cells, cell morphology, and oxygen uptake rate (OUR) was established. DS could be used to detect viable R. sphaeroides cells, and the relationship among cell morphology, CoQ 10 biosynthesis, and OUR was found to be significant. Based on this model, the online specific oxygen consumption rate (Q O2 ) control strategy was successfully applied to the CoQ 10 fermentation process. Q O2 controlled at 0.07 ± 0.01 × 10 − 7 mmol/cell/h was most favorable for CoQ 10 biosynthesis, resulting in a 28.3% increase in CoQ 10 production. Based on the multi-parameters analysis and online Q O2 control, a precise online nutrient feeding strategy was established using conductivity detected by DS. CoQ 10 production was improved by 35%, reaching 3384 mg/L in 50 L bioreactors. This online control strategy would be effectively applied for improving industrial CoQ 10 production, and the precise fermentation control strategy could also be applied to other fermentation process.