Nigeran production in some Aspergillus and Penicillium species.

Thirteen additional members belonging to genera Aspergillus and Penicillium were found to be nigeran producers. Nigeran content was found to increase under carbon and nitrogen depletion and metal toxicity. Among the three metal ions--copper, iron and magnesium--copper was found to have the greatest effect in increasing nigeran content. Nigeran production varies from strain to strain and the amount is greatly influenced by environmental conditions.