Effects of dissolved oxygen concentration and DO-stat feeding strategy on CoQ10 production with Rhizobium radiobacter

The cell growth and CoQ(10) ( coenzyme Q(10)) formation of Rhizobium radiobacter WSH2601 were investigated in a 7-l bioreactor under different dissolved oxygen (DO) concentrations. A maximal CoQ(10) content (C/B) of 1.91 mg/g dry cell weight (DCW) and CoQ(10) concentration of 32.1 mg/l were obtained at the appropriate DO concentration of 40% (of air saturation). High DO concentration was favourable to the cell growth of Rhizobium radiobacter WSH2601. In order to achieve the maximal yield of CoQ(10) production, a new DO-stat feeding strategy was proposed, which significantly improved cell growth and CoQ(10) formation. With this strategy, the maximal CoQ(10) concentration and DCW reached 51.1 mg/l and 23.9 g/l, respectively, which were 67 and 44.8% higher than those obtained in the batch culture with DO concentration controlled.