Lovastatin biosynthesis by Aspergillus terreus in a chemically defined medium

Lovastatin is a secondary metabolite produced by Aspergillus terreus. A che mically defined medium was developed in order to investigate the influence of carbon and nitrogen sources on lovastatin biosynthesis. Among several or ganic and inorganic defined nitrogen sources metabolized by A. terreus, glu tamate and histidine gave the highest lovastatin biosynthesis level. For cu ltures on glucose and glutamate, lovastatin synthesis initiated when glucos e consumption levelled off. When A. terreus was grown on lactose, lovastati n production initiated in the presence of residual lactose. Experimental re sults showed that carbon source starvation is required in addition to relie f of glucose repression, while glutamate did not repress biosynthesis. A th reefold-higher specific productivity was found with the defined medium on g lucose and glutamate, compared to growth on complex medium with glucose, pe ptonized milk, and yeast extract.