The effects of aeration rate and agitation speed on ubiquinone-10 (CoQ10) sub-merged fermentation in a stirred-tank reactor using Pseudomonas diminuta NCIM 2865 were investigated. CoQ10 production, biomass formation, glycerol utilization, and volumetric mass transfer coefficient (k(L)a) were affected by both aeration and agitation. An agitation speed of 400 rpm and aeration rate of 0.5 vvm supported the maximum production (38.56 mg L-1) of CoQ10 during batch fermentation. The fermentation run supporting maximum production had an k(L)a of 27.07 h(-1) with the highest specific productivity and CoQ10 yield of 0.064 mg g(-1)h(-1) and 0.96 mg g(-1) glycerol, respectively. Fermentation kinetics performed under optimum aeration and agitation showed the growth-associated constant (a = 5.067 mg g(-1)) to be higher than the nongrowth-associated constant (beta = 0.0242 mg g(-1)h(-1)). These results were successfully utilized for the development of fed-batch fermentation, which increased the CoQ10 production from 38.56 mg L-1 to 42.85 mg L-1.