19-08-2014, 11:33 AM
Secondary metabolites roduced from the Monascus species include (i) group of pigments âââ‰â¬Å yellow, orange and red (ii) group of monacolins including monacolin K (lovastatin) (iii) citrinin (monascidin ) (iv) others like GABA, dimerumic acid, monakarines, ankalactone and monascodilone. Lovastatin inhibits 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the rate-limiting enzyme in cholesterol biosynthesis, and thus used in the treatment of hypercholesterolemia.
Secondary metabolites roduced from the Monascus species include (i) group of pigments – yellow, orange and red (ii) group of monacolins including monacolin K (lovastatin) (iii) citrinin (monascidin ) (iv) others like GABA, dimerumic acid, monakarines, ankalactone and monascodilone. Lovastatin inhibits 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the rate-limiting enzyme in cholesterol biosynthesis, and thus used in the treatment of hypercholesterolemia. Red pigments are used as a food colorant. The yellow and orange pigments show antimicrobial activity, embryotoxicity and immunosuppressive effects.
The present work was initiated with screening of several strains of Monascus purpureus for the highest lovastatin producer by solid state fermentation (SSF) as well as with submerged fermentation (SmF).
The strain M. purpureus MTCC 369 gave maximum lovastatin production of 1 mg/g dry fermented matter (DFM) in a defined medium consisting of rice, NH4Cl, KH2PO4, MgSO4.7H2O, MnSO4.H2O after 240 hrs, and was selected for further work. For the optimization of SSF media, several solid substrates such as oil cakes, tubers, and cereals were screened. The highest lovastatin production was obtained with parimal rice as substrate and hence further optimization was done with respect to parameters such as initial moisture content, inoculum size and pH by one factor at a time and later by response surface methodology.
Thin layer chromatography was done with the solvent system as cyclohexane: chloroform: isopropanol (5:2:1). On the basis of these results, silica gel chromatography was performed and separation of lovastatin and red pigments was achieved. The extraction of lovastatin via supercritical fluid extraction is in progress. As lovastatin exists in two forms a lactone form and hydroxy acid lovastatin, both the forms were quantified by high performance liquid chromatography (HPLC), while the pigments were analyzed spectrophotometrically at 400, 470 and 500 nm for yellow, orange and red pigments respectively.