Auxithals Synthesized By Some Filamentous Fungi1

Abstract

Six fungi, some auto-trophic, some partially heterotrophic, and some completely heterotrophic, were tested for their ability to synthesize thiamin, thiamin moieties, and biotin. Some 40 filamentous fungi were used as test organisms. All 6 of the fungi synthesized biotin from a synthetic medium; most of it was stored in the mycelium, but appreciable quantities diffused into the nutrient soln. in which they were grown. The autotrophic fungi synthesized thiamin also, retaining all of it in the mycelium but giving off into the soln. the 2 moieties. The partially or completely heterotrophic organisms behaved the same way, except that the latter type fungi which cannot grow without the presence of the complete molecule of thiamin, removed all of it from the medium and excreted the moieties. Mucor ramannianus, when furnished with thiazole only, grew very well but synthesized small quantities of thiamin, thiamin moieties, and biotin. But when both thiazole and pyrimidine were added to the nutrient medium, the amt. of thiamin and its moieties was increased considerably; biotin remained unaffected.