The Effect Of Flavonoids On The Production Of Polysaccharides By The Monascus Strains In Liquid Fermentation And Optimization Of Fermentation Process Conditions

In this paper,by adding flavonoids to the liquid fermentation medium of four monascus strains,the effects of the flavonoids on the production value,structure and physiological activity of polysaccharides produced by the liquid fermentation of monascus were investigated.And optimized the liquid fermentation process conditions of monascus extracellular polysaccharide.First of all,the effect of flavonoids on the production of crude exopolysaccharides was studied.Five different flavonoids are added respectively,and it is found that the crude exopolysaccharide value is related to the type of flavonoids.Some of the selected five flavonoids can promote the production of crude extracellular polysaccharides,and some can inhibit them.For example,for Monascus aurantiacus AS3.4384,the addition of quercetin increases the production of crude extracellular polysaccharides to 2.14 g/L,the relative blank increased by 40.8%,the addition of daidzein reduced the yield of crude extracellular polysaccharide to 1.15g/L,and the relative blank decreased by 24.3%respectively.The pigment production capacity of Monascus aurantiacus AS3.4384 was the lowest,so it was selected.The addition of quercetin increased the value of crude extracellular polysaccharide by11.66%.At this time,the citrinin output value was 15.56μg/m L in the blank group,and the citrinin in the experimental group was reduced to 2.59μg/m L.Next,the physicochemical properties of extracellular polysaccharides produced by adding genistein to four monascus strains in liquid fermentation were determined,and the differences in physicochemical properties of intracellular polysaccharides and extracellular polysaccharides were compared,including the appearance and texture of pure polysaccharides,yield,sugar composition,molecular weight,monosaccharide composition,electron microscope analysis,TGA analysis,XRD analysis and FI-IR analysis.The extracellular polysaccharide was verified by HPLC,and it was found that there were only extremely small and weak absorption peaks around the peak time of genistein standard product at about 5.333 min,and the peak area was not displayed in the integration results.Then the extracellular polysaccharides obtained by liquid fermentation of four monascus strains added with flavonoids were subjected to in vitro antioxidant determination and the proliferation and phagocytic activity of Raw264.7.Four strains of exopolysaccharide blank groups and experiments Group,the ability to remove DPPH·and-OH·is better,the highest can reach and 95.09%respectively,and the extracellular polysaccharides of 30141 bacteria added luteolin and 4384 bacteria added quercetin have better ability to remove ABTS⁺·,60.29%and54.88%respectively.Then,the immune activity of the extracellular polysaccharides obtained by liquid fermentation of the four monascus strains after adding genistein was preliminarily determined.From the perspective of the effect on the proliferation of Raw 264.7 cells,the four strains of monascus exopolysaccharide’s blank group and experiment group both had a proliferation effect on cells,and showed a very significant increase,P<0.001,and the experimental group after adding genistein was better.In particular,40269 added genistein,the cell proliferation rate of the experimental group was 169.98%at 200μg/m L,which has exceeded the cell proliferation rate of 160.36%in the LPS group at 3μg/m L.From the influence on the phagocytic activity of Raw 264.7 cells,the blank groups and the experimental groups both improved the phagocytic activity,and the phagocytic activity was stronger after the addition of genistein,with 4384 and 40269 showing significant In particular,P<0.001 at a higher dose of 200μg/m L showed a very significant improvement.In particular,the phagocytic activity of the 40269 added with genistein in the experimental group was 143.88%at 200μg/m L,Less than and close to 159.97%of the phagocytic activity of the LPS group.Finally,the optimization of liquid fermentation process conditions for the crude extracellular polysaccharides of monascus and the preparation process of intracellular and extracellular polysaccharides.As a strain optimized for subsequent flavonoid addition,medium composition and culture conditions,the best way to obtain exopolysaccharide production by Monascus aurantiacus AS3.4384:sucrose yeast extract liquid fermentation medium:50 g/L sucrose,3.5 g/L yeast extract powder,1g/L quercetin,1.0 g/L Mg SO₄·7H₂O,0.9 g/L KH₂PO₄,1.8 g/L K₂HPO₄·3H₂O,2m L/L Tween-80,natural p H（5.5）,the inoculation amount is 9%,the seed age is 52 h,the shaker speed is 180 r/min,and the fermentation culture is 100 h.At this condition,the value of fermented crude extracellular polysaccharide reached the maximum,which was 7.018 g/L.