Biotin and the biosynthesis of anthraquinoid pigments in Penicillium islandicum Sopp.

By use of liver enzyme preparations, it has been proved that biotin is required for the synthesis of fatty acids (S. J. Wakil, Lipid Res. 2:1, 1961). Biotin-containing enzyme, acetyl-coenzyme A (CoA) carboxylase, catalyzes the first step in the reaction, and the malonyl-CoA produced is the first intermediate of the biosynthesis of the anthraquinoid pigment in fungi (S. Gatenbeck, Acta Chem. Scand. 16:1053, 1962). Aside from this, little information is available on the mechanism of microbial biosynthesis of anthraquinone. In this note, the relationship between biotin and synthesis of anthraquinoid pigments and the role that biotin has in the synthesis of the pigments are discussed. Stationary cultures of Penicillium islandicum Sopp strain E, which was isolated from a yellowed rice by H. Tsunoda, Food Research Institute, Tokyo, were made at 28 C on 50 ml of Czapek medium in 200-ml Erlenmeyer flasks. On the 6th and 14th days of culture, the mycelium was harvested, and total pigments of the dried mycelia were extracted with acetone after removal of mycelial lipids with n-hexane (T. Tatsuno, Prod. Pharm. 18:180, 1963). The amounts of pigments were determined by weighing the residue after evaporation of acetone. Biotin-deficient mycelium of P. islandicum was obtained by cultivating the fungus on the Czapek medium containing 5 units of avidin (Nutritional Biochemicals Corp., Cleveland, Ohio), and the reactivation of the biotin-deficient fungus was carried out by the addition of 0.1 ,umole of biotin per flask (Table 1). The addition of avidin diminished significantly the amount and percentage of pigments without affecting the fungal growth in both stages, and biotin reactivated partially the depressed pigmentation of avidin-treated fungus. Neither growth nor pigment formation was affected by supplemental biotin.