[Effect of the age of the culture and the composition of the medium on alkaloid biosynthesis by Penicillium gorlenkoanum].

The production of the alkaloids costaclavine and epicostaclavine by Penicillium gorlenkoanum was studied as a function of the culture age and the composition of the growth medium. The alkaloids were found in the mycelium and, in great quantities, in the cultural broth. The production of the extracellular alkaloids started from the first days of growth and run in parallel to the biomass accumulation; the synthesis of costaclavine and epicostaclavine was maximal at the end of the logarithmic-stationary growth phases. The medium supplied with mannitol, succinic acid and 1% KH2PO4 was optimal for epicostaclavine synthesis. A carbohydrate or organic acid substitution as well as a variation in the concentration of phosphate changed the proportion between epicostaclavine and costaclavine contents. The biosynthesis of epicostaclavine was inhibited almost entirely by the glucose deficiency (2%) in the medium. This glucose concentration, phosphate excess (10 g/l), and the presence of citric or tartaric acids created favourable conditions for costaclavine biosynthesis.