Studies on Screening and Fermenting Condition of Monascus Producing Monacolin K

Abstract: In 1979, A. endo in Japan found that M.rubber could produce Monacolin K , which is cholesterol synthesizing inhibitor. Researchers both in china and abroad have been making study of it since then. The molecular structure and the safety of physiological active materials were studied in details. Its value of medicine has been given especial attention to among researchers in the world. After MERCK developed Mevacor that can decrease the content of the cholesterol, a series of statins were developed. However, the study of Monascus of decreasing cholesterol falls behind relatively in our country. The source of Lovstatin was produced firstly in 1996. Up to now, reasons that the production of Monacolin K is low and operating costs is high in our country are the lack of Monacolin K Monascus strains and the lack of qualified industrial fermentation. Therefore, the isolation of Monascus that is over-production Monacolin K is very important. And the detection of Monacolin K and fermentation condition were studied. The results as follows:1. The detection methods of Monacolin K concent in Monascus products were investigated. The content of Monacolin K was determined by HPLC. Monacolin K was separated on a kromasil C18 column (5um,250 X4. 6mm) using methanol-water (87:13 V/V) as the mobile phase and flow rate 0. 6ml/min with detection at 238nm. Under such chromatographic condition, Monacolin K can be determined. The method demonstrated a good linear relationship , separation degree and repeatability. The average rate of recovery of Monacolin K was 99.23%, the relative standard deviation(RSD) was 0. 38%.2.45 strains of Monascus were isolated from 60 samples mainly from the red rice and so on. 9 strains were proved to produce Monacolin K. Among them, M32 can produced higher Monacolin K.3.In the paper, colony characteristics, optic microscopic observation thestrains and the biological features of the M32 Monascus strains were studied. Its growth temperature was 25-35C, the optimum original pH of spore budding and mycelium growth was 4. 0-6. 5, the resistance ability to ethanol was as high as 14%. An optimum medium was obtained through single factor tests and optimization tests. During the research, we found that the addition of 1g/1 MgSO4 and 2g/l ZnSO4 could improve the Monacolin K value. And we got the optimum medium: glycerine90g/l, rice meal20g/l, amylaselg/1,peptone10g/1, NaNO35g/l, MgSO41g/1, ZnS042g/l, KH2PO42.5g/l. The most moderate breeding condition for fermentation is: Temperature 25C,the original pH for medium is 5. 0, The volume of fermentation solution is 200ml in 500ml Erlenmeyer flash , the rocking bed velocity is 150r/min, fermentation time is 12 days. In submerged fermentation with optimum medium and optimum fermentation condition, The concentration of Monacolin K can be reached to 700-800mg/l…
Key words: Monascus Monacolin K; Isolation; Screening; fermentation Condition

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