[Role of tryptophan and histidine in alkaloid biosynthesis by Penicillium roqueforti].

The effect of L-tryptophan, L-histidine and DL-mevalonic acid on the content of intra- and extracellular alkaloids was studied in Penicillium roqueforti. The regulatory action of the compounds was found to depend on the cultural age, the concentration of the compounds, and the time at which they were added to the medium. Exogenous tryptophan produced the strongest stimulatory effect on roquefortine biosynthesis, and the weakest effect on the production of clavine alkaloids. Histidine (5-10 mM) stimulated (by a factor of 3-4) the accumulation of extracellular dihydroroquefortine in the 'young' culture, but inhibited its synthesis in the 8-day-old fungus. Mevalonic acid had no effect on the biosynthesis of clavine alkaloids, but inhibited the production of roquefortine and dihydroroquefortine.