Studies in the Biochemistry of Micro-organisms. Part XIV.—On the production and chemical constitution of a new yellow colouring mater, citrinin, produced from glucose by Penicillium

It has been known for some time thatPenicillium citrinum Thom when grown on suitable media produces a characteristic lemon yellow colour. Thus Thom in his monograph on “Cultural Studies of species ofPenicillium ” (1910), says, “P. citrinum produces a lemon yellow colour, soluble in alcohol, in media containing sugars, milk, gelatin, bread and potato.” This colouring matter was not isolated, however, nor was its nature further investigated. In the course of an investigation into the colour reactions given with ferric chloride by metabolism solutions produced by various species ofPenicillium , it was found that a very characteristic reaction was given by each of the strains ofPenicillium citrinum THOM in our possession, but was not given by any other species in pure culture whether ofPenicillium or of any other genus tested.