Research of Monacolin K Production by Liquid Fermentation of Monascus SPP.

Abstract: Monacolin K, a bioactive substrate produced by Monascus spp., is one of the focuses on Monascus research. And it is expanding to industrialization. The main purpose of this thesis is to study the fermentation technology of Monacolin K by liquid fermentation of Monascus spp..Five Monascus spp. from our collections were screened. At last, we decided GM088 which had higher yield of Monacolin K comparatively to be the object strain for our study.The method which determines the content of Monacolin K was studied. The optional condition for HPLC was decided.The effects of carbon source, nitrogen source , inorganic salts, possible precursor antifoams as well as some particular substances on Monacolin K production were studied. The compound carbon source was appropriate for Monacolin K production. 5% glycerok 1% glucose, 1% soluble starch were used as the best carbon source. The compound nitrogen source was appropriate for Monacolin K production just as compound carbon source.3.8% peptone made from soybean, 0.2% NaNO3 were used as the best nitrogen source. Among all the inorganic salts studied, CaCb and CoCb could largely enhance Monacolin K production; KH2PO4 could slightly enhance Monacolin K production; whereas ZnSO^ MnSO4 and FeSC^ could inhibit Monacolin K production; MgSO4 and KC1 had no significant effects on Monacolin K fermentation. Also the possible precursors were tested. Sodium acetate could increase Monacolin K production. Adding of sodium acetate with small scale time after time was better than the adding of it with large scale in one time. Met amino acid had no significant effect on Monacolin Kproduction. Besides, the optional time to add sodium acetate and Met in certain proportion was during the middle time of the whole fermentation process. Among antifoams studied, GPE had certain inhibitory effect on Monacolin K production; while PEG2000 had slight effect on Monacolin K production. Some substances from nature have certain factors which may be required for the growth of microbes. We found such substances from nature had obvious effects on Monacolin K production.Fed-batch fermentation was a more effective mode for Monacolin K production compared with batch fermentation. The effects of glycerol adding were studied. The best concentration of glycerol and ways of adding were found. An increase of overall Monacolin K productivity of 81.39% was achieved when 0.25% glycerol was added into the medium during 5 , 6, 7, 8 days of fermentation.The relationship among growth of Monascus, Monacolin K and pigment production were studied elementarily. There were no positive relations in correspond between growth of Monascus and the production of Monacolin K & pigment. No obvious correlations were found between Monacolin K and pigment production…
Key words: Monascus spp.; Monacolin K; liquid fermentation; fermentation technology

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