Monascus Extraction Fermentation And Regulation Of The Secondary Metabolites

Cloud point system can be established for extraction fermentation by adding a certainamount of nonionic surfactant Triton X-100in the conventional microbial fermentationsystem. Submerged cultivation of Monascus in the nonionic surfactant Triton X-100micelleaqueous solution, Monascus growth does the same as conventional fermentation exceptingthere is a relative long lag phase. In the extraction fermentation system, the permeabilizationof intracellular Monascus pigments across the cell membrane and the extraction of thepigments to the nonionic surfactant micelles in fermentation broth occur simultaneously. Nowthe cloud point extraction system has attracted much more and more researchers’ concerns.However, the knowledge of the mechanism of nonionic surfactant affected the permeability ofmembrane and perstractive fermentation was very limit.The mechanism about the perstractive fermentation in nonionic surfactant micelleaqueous solution was studied by submerged cultivation of Monascus in the nonionicsurfactant Triton X-100micelle aqueous solution. The permeabilization of intracellularpigments across the cell membrane to the extracellular fermentation broth has been intensified.The extracellular pigments concentration was depended with the nonionic surfactant, theconcentration of nonionic surfactant and the total production of Monascus pigments. Thestronger extraction ability of nonionic surfactant in the fermentation broth，the higherextracellular pigments concentration it is. The higher Monascus pigments total production, thehigher extracellular pigments concentration it is. In conclusion, the export of intracellularMonascus pigments are mainly related to the solubilization capacity of nonionic surfactantmicelles. The type and concentration of nonionic surfactant are important factors affect theextractive fermentaion.Effect of nitrogen source, pH and nonionic surfactant on profile of intracellular andextracellular Monascus pigments, components of pigments and production of citrinin werestudied respectively. The results indicated that the final pH of fermentation broth plays a keyrole in regulation of the profile of intracellular and extracellular Monascus pigments,components of pigments and the production of citrinin. The concentration of extracellular Monascus pigments and red pigment increased with the increase of the final pH offermentation broth. Conversely，there were very few extracellular Monascus pigments and redpigment in a low final pH fermentation system. More interestingly, in low final pH（below3.0）fermentation system, the biosynthesis of citrinin was inhibited. There was nocitrinin detected out both in the intracellular and extracellular Monascus pigments by TLCanalysis in a low final pH fermentation system. Citrinin was detected out both in theintracellular and extracellular when the final pH of fermentation broth above3.0. Theextracellular citrinin production increased with the increase of the final pH of fermentationbroth. The final pH of fermentation broth was related with nitrogen source and the initial pHof fermentation broth. Nitrogen source and the initial pH of fermentation broth regulated theprofile of intracellular and extracellular Monascus pigments, components of pigments and theproduction of citrinin by regulating the final pH of fermentation broth. On the other hand, theinfluence of nonionic surfactant Triton X-100on profile of intracellular and extracellularMonascus pigments markedly while has nothing to do with the pH of fermentation broth.Production of high concentration citrinin-free intracellular orange pigment can be realized bysubmerged cultivation of Monascus in conventional fermentation system by controlling anextremely low pH. On the contrary， production of high concentration citrinin-freeextracellular yellow pigment also can be realized by submerged cultivation of Monascus inthe nonionic surfactant Triton X-100micelle aqueous solution by controlling an extremelylow pH.