EXTRACTION AND PURIFICATION OF LOVASTATIN FROM NONAFLATOXIGENIC STRAINS OF ASPERGILLUS FLAVUS
A common plant and human pathogen can be employed to synthesize a sterol of significance to mankind. Aspergillus flavus is known for its ability to synthesize harmful aflatoxins, which is the main cause of aspergillosis in man. It has been found that not all strains of Aspergillus flavus are toxic in nature, and the non-aflatoxic strains have the ability to synthesize the secondary metabolite - Lovastatin. Lovastatin competitively inhibits HMG-CoA, thereby reducing the levels of blood cholesterol. Ethyl acetate and acetonitrile have proved to be good solvents for extraction. Purification of lovastatin extract can be carried out using silica gel based column chromatography. The concentration of extracted lovastatin, both crude and purified, was estimated by using HPLC. The concentrations of the extract, as compared to lovastatin standard were found to be 7.14 mg/mL for crude extract and 8.01mg/mL for purified extract. Since lovastatin production is directly proportional to biomass production, altering the carbon source, nitrogen source, phosphate source and dissolved oxygen have played significant roles in varying the concentration of lovastatin synthesized. UV mutation has found to have no effect on increasing the level of synthesis of lovastatin. However, exposure to UV mutation results in complete loss of biosynthetic activity of Aspergillus flavus