Abstract

PENICILLIUM SCLEROTIORUM 39 Dox medium which contains 1.0 g.NaNO3/l.(0.1 %).As the nitrate concentration is further increased, the growth, indicated by the mycelium yield and the production of solerotiose, is progressively reduced.While Fig. 1 indicates that maximum KCl con- sumption is obtained on media of low nitrate content, Fig. 2 shows a parallelism of sclerotiorine production with growth, in nitrate concentrations up to 0-2 %, and hence independence of the KCI consumption.Above 0-2 % sodium nitrate, it would appear that pigment production is inhibited by the nitrate.As this is also true of KCI utilization, it may be asserted that the production of sclerotiorine is responsive to nitrate concentration only when this factor greatly reduces the amount of KCI metabolized by the organism.The facts justify the previous assertion that pigment production is merely a by-product of the chloride consumption.SUMMARY 1.The KCl metabolism of PeniUium 8clerotiorum is an inverse function of the nitrate concen- tration of the culture medium, and the pigment yield is unaffected until such time as the chloride consumption is much reduced below normal.2. The production of sclerotiose is almost inversely proportional to the nitrate content of the medium, yields in excess of 10 % being obtained on a substrate in which .the nitrate concentration is half that usually used, as compared with 3 % for the standard (0-2 % NaNO3) medium.