Pigment Production in Certain of the Aspergillus Glaucus Group

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Abstract
Auroglaucin and flavoglaucin are major end products of carbohydrate metabolism among members of the Aspergillus glaucus group. Striking quantities of these pigments are produced in both surface and submerged cultures. Even after considerable growth has developed, aerobic conditions are essential for pigment formation. In surface culture, organisms grown on glycerol, mannitol and xylose produced almost twice the amount of pigment per gram of mycelium as those grown on glucose. In submerged culture, organisms grown on glycerol produced even higher ratios of pigment per gram of mycelium than comparable glucose growths. In a basal Czapek-Dox solution no growth could be obtained in surface or submerged culture with either pyruvate, lactate, propyl alcohol or ethylene glycol as the sole carbon source. In submerged culture M/5000 and M/10,000 iodoacetate added the third day of growth inhibited both growth and pigment production on glucose while M/1000 iodoacetate inhibited neither growth nor pigment production on glycerol. In submerged culture M/250 sodium fluoride inhibited pigment production on glucose while concentrations as high as M/25 failed to inhibit production on glycerol. M/1000 iodoacetate markedly affected growth and pigment production on glucose, mannose, fructose, xylose, rhamnose and dulcitol; growth and pigment production on glycerol, mannitol and sorbitol was affected little or not at all. Pigment production by washed “resting preparations” on glucose is inhibited by concentrations of iodoacetate far too weak to inhibit production on glycerol, sorbitol and mannitol. Soluble intermediates in the growth medium may play a significant role in pigment production. The data presented suggest that the following tentative pathway may be involved in pigment synthesis by members of the A. glaucus group. Glucose is dissimilated by the usual route of carbohydrate dissimilation in yeast to the three carbon stage; the three carbon compound is then condensed to a six carbon residue such as mannitol, which is then converted in some yet undetermined manner to the pigments.

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