Optimization of a culture medium for increased mevinolin production by Aspergillus terreus strain

Abstract

Fungi are important sources for the production of some pharmaceutical compounds. e.g. lovastatin, mevinolin and monacolin K. These are competitive inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A reductase, the rate limiting enzyme of cholesterol synthesis pathway. Four fungal strains of Aspergillus terreus and one Penicillium patulum were tested for their potential to produce mevinolin. The fungal strains were cultivated in four different semi-synthetic media to select a fermentation medium and a fungal strain that has the ability to secret mevinolin in high yield. The fermentation followed by TLC screening. Positive results were evaluated by confirmatory HPLC. A. terreus J9 was the best strain for producing mevinolin with a level of 148.66 mg/L of Dox-rice medium. Cultivation a 7.5 L in fermenter, A. terreus J9 produced 932.15 mg/L after 96 h using Dox-rice medium at 6.5 pH. Rise in acidity or alkalinity decrease mevinolin producing ability. Ammonium sulphate in the medium as sulphur and nitrogen sources influenced greatly mevinolin production as well as incubation period. Maximum production was obtained after 36 h incubation. The maximum value of the mevinolin concentratiom (1761.6 mg/L) was attained at 400rpm after 60 h fermentation at 28 oC. The optimized medium resulted in a significant increase of mevinolin cocentration, as compared with that obtained by the fermentation of many other A. terreus species.