Influence of Substrate Feeding and Process Parameters on Production of Coenzyme Q₁₀ Using <i>Paracoccus denitrificans</i> ATCC 19367 Mutant Strain P-87

Abstract

Coenzyme Q 10 (CoQ 10 ), an important antioxidant molecule playing a major role in electron transport chain, has been commercially produced by fermentation process for the use in oral nutraceutical formulations. Constructing the high-yielding CoQ 10 producing strains is a pre-requisite for cost-effective production. A superior mutant strain P-87 generated from Paracoccus denitrificans ATCC 19367, which showed 1.25-fold improvement in specific CoQ 10 content higher than the wild type strain at shake flask level, was selected to carry out the studies on CoQ 10 yield improvement through fermenter process optimization. In the course of study, initially the cane-molasses-based medium and fed-batch fermentation strategy using pHBA in combination with sucrose were standardized in shake flask using wild type strain. This strategy was subsequently translated at 2 L laboratory fermenter while optimizing the fermentation process parameters using improved mutant strain P-87. Under optimized fermentation condition, mutant strain P-87 produced 49.85 mg/L of CoQ 10 having specific content of 1.63 mg/g of DCW, which was 1.36 folds higher than the specific CoQ 10 content of wild-type strain under similar optimized condition. The temperature and DO were found to be critical parameters for CoQ 10 production by mutant strain P-87. The optimum temperature was found to be 32 ° C and the optimum DO concentration to be maintained throughout the fermentation cycle was found to be 30% of air saturation. Overall, a new cost-effective process has been established for the production of CoQ 10 using the cheaper substrate “cane molasses” and higher CoQ 10 producing mutant strain P-87.