| Monascus pigment is the only kind of pigment that is produced by microorganism fermentation.The liquid deep fermentation of Monascus pigment has high automation,low labor force,less pollution and other advantages gradually replace the traditional solid state fermentation,but the production of pigment is still low,the extraction process is large and the cost is high.On the basis of the previous research of the project group,this paper further studied the conditions for the production of Monascus pigment from the liquid fermentation of Monascus purpureus 183-3,the conditions for inhibiting the synthesis of citrinin,the extraction process of the Monascus pigment in the mycelial cells and the stability of the Monascus pigment.The main results are as follows:1?The culture medium of Monascus pigment produced by liquid fermentation of Monascus purpureus 183-3 was optimized.The results showed that ammonium salt could inhibit the synthesis of citrinin and the accumulation of Monascus pigment in the cell.The optimized fermentation medium was composed of maltodextrin 10%,ammonium sulphate 0.20 mol/L,MgS04"7H20 0.1%,MnS04"H20 0.017%,ZnS04"7H20 0.018%,initial pH 5.0 of culture medium,inoculation amount 10%(v/v),medium volume 50 mL/250 mL,rotation speed 180 rpm,and temperature 32O? fermentation time 10 d,cytosolic red pigment 1249.74 U/g,orange pigments 1113.75 U/g and yellow pigment 971.25 U/g were 55.44%,45.87%and 14.40%higher than that before optimization,respectively.Citrinin decreased from 526.64 mg/kg before optimization to 5.88 mg/kg.2.?The conditions of Monascus pigment in the 5 L fermentor of Monascus purpureus 183-3 were two grade seed culture,the fermentation agitator was six-hinge stirrier DT602,the dissolved oxygen was maintained at 40±5%,the fermentation pH was maintained at 3.5±0.5,the concentration of ammonium sulfate was 0.20 mol/L,and the amount of Maltodextrin was 10%,when fermentation 5 d,6 d,7 d respectively supplementation.The Concentration of 20%maltodextrin was 200 mL,200 mL,100 mL,and 10 d was fermented.The content of intracellular pigment was determined(calculated by wet mycelium per gram),red pigment was 1645.75 U/g,orange pigment 1546.75 U/g,and yellow pigment 1497.25 U/g,which were 31.69%,38.88%and 54.16%higher than that of shake flask experiment.Further amplification test of 50 L fermentor,red pigment 1503 U/g,orange pigment 1451.25 U/g,yellow pigment 1253.25 U/g,compared with the experimental results of shake flask,respectively,increased by 20.27%,30.30%,29.03%,butslightlylower than thelevel of 5Lfermentor.3?The optimum conditions for the extraction of Monascus pigment from the dry powder of Monascus purpureus 183-3 mycelium were as follows:liquid ratio 300:1,ethanol concentration 75%(v/v),temperature 50?,pH 4.0,and extraction time 3 h,the red pigment content of mycelium dry powder was 7212.00 U/g,orange pigment 7032.00 U/g,and yellow pigment 7716.00 U/g.4.?The study on the stability of Monasrcus pigments showed that Monasctus pigments were easily decomposed at high temperature,and red pigment was more sensitive to light.Monascus pigment was stable at a wide range of pH,but over acid and over alkali can lead to the degradation of pigment.Therefore,the storage conditions of Monascus pigment are:light avoidance,temperature below 50?,and pH maintained at 3.0-7.0. |
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