Coenzyme Q in Thraustochytrium sp. RT2316-16: Effect of the Medium Composition

Coenzyme Q (CoQ; ubiquinone) is an essential component of the respiratory chain. It is also a potent antioxidant that prevents oxidative damage to DNA, biological membranes, and lipoproteins. CoQ comprises a six-carbon ring with polar substituents that interact with electron acceptors and donors, and a hydrophobic polyisoprenoid chain that allows for its localization in cellular membranes. Human CoQ has 10 isoprenoid units (CoQ(10)) within the polyisoprenoid chain. Few microorganisms produce CoQ(10). This work shows that Thraustochytrium sp. RT2316-16 produces CoQ(10) and CoQ(9). The CoQ(10) content in RT2316-16 depended strongly on the composition of the growth medium and the age of the culture, whereas the CoQ(9) content was less variable probably because it served a different function in the cell. Adding p-hydroxybenzoic acid to the culture media positively influenced the CoQ(10) content of the cell. The absence of some B vitamins and p-aminobenzoic acid in the culture medium negatively affected the growth of RT2316-16, but reduced the decline in CoQ(10) that otherwise occurred during growth. The highest content of CoQ(9) and CoQ(10) in the biomass were 855 μg g(−1) and 10 mg g(−1), respectively. The results presented here suggest that the thraustochytrid RT2316-16 can be a potential vehicle for producing CoQ(10). Metabolic signals that trigger the synthesis of CoQ(10) in RT2316-16 need to be determined for optimizing culture conditions.