Enrichment of vitamin D in mycelium from submerged cultures of the agaric mushroom .

Ergosterol, a precursor of vitamin D, is present in the cell membrane of all fungi. It can be transformed into vitamin D by UV-B exposure. In this study, a basidiomycete, , cultivated in liquid malt extract medium was exposed to UV-B light. In addition, autoclaved, abiotic mycelium was put through UV-B exposure for the first time. The effects of different UV-B exposure times, surface areas and temperatures on vitamin D formation were analyzed. The conversion of ergosterol to vitamin D at ambient temperature almost reached completion within 10 min resulting in vitamin D concentrations of 365 µg (g dry matter). Prolonged exposure of the biotic mycelium for up to 60 min resulted in a reduced vitamin D concentration with stagnation at about 280 µg (g dry matter). Exposure of the abiotic mycelium showed a slower increase but also leveled off at the same concentration. Furthermore, it could be shown that vitamin D formation depends on the temperature and the exposed surface area. The vitamin D concentration augmented after increasing the exposed surface from 65.0 to 298.6 cm. The ergosterol content of was analyzed in a way similar to vitamin D and resulted in 3.75 ± 0.06 mg (g dry matter) ergosterol.