Ergosterol content of Rhizopus oligosporus NRRL 5905 grown in liquid and solid substrates

Summary The ergosterol content of Rhizopus oligosporus NRRL 5905 varied between 2–24 g/ mg biomass dry matter when grown in laboratory media and was found to be influenced by the substrate composition.When grown on a natural substrate (soya beans) the ergosterol content was considerably higher (estimated at approx. 60–90 g/mg biomass dry matter).In laboratory media, the ergosterol content was also influenced by the extent of aeration and the growth phase of the mycelium; within the range of 25° C–35° C, the incubation temperature did not influence the ergosterol content significantly.In view of these variations, ergosterol should not be used as a chemical index for the quantification of biomass grown in static solid-substrate fermentations with limited mass transfer, e.g. tempe or oncom.