Fermentation,Purification And Characteristic Analysis Of Yellow Pigment From Epicoccum Nigrum YL01

In this paper,the fermentation conditions of the extracellular yellow pigmentproduced by Epicoccum nigrum YL01 were optimized,and preliminary studies have been done on the synthesis pathway,purification and physical and chemical properties of extracellular yellow pigment.The technology was optimized by single factor and response surface experiments.,the medium ratio was obtained as:1.646%glycerol,0.2%yeast powder,0.05%zinc chloride,natural p H,and the seed medium and fermentation medium use this ratio;shaker culture conditions were as follows:temperature 23.05?,time 12 d,rotating speed 150r/min,filling volume 95.1mL/250mL.This method can obtain a higher yield of extracellular yellow pigment with a color value of 16.646U/mL.It was preliminarily determined that the synthetic pathway of yellow pigment produced by Epicoccum nigrum YL01 was the shikimic acid pathway throughenzyme inhibition and addition methods.When the inhibitor trimethylamine was 12mmol/L,the yellow pigment production decreased by 80.24%;when the precursor substance enhancer tyrosine was 6mmol/L,the yellow pigment yield increased by88.90%compared with the control,and the phenylalanine was 3mmol/L The yield of yellow pigment at increased by 107.83% compared with the control.The separation and purification conditions of Epicoccum nigrum YL01 yellowpigment were optimized.The extraction of n-butanol by organic solvents was better.The ratio of fermentation broth to n-butanol was 2:3,and the extraction wasperformed 3 times.Silica powder was selected as the column material,and ethyl acetate,ethanol,and water are used as mobile phases to separate and purify yellow.pigment.After HPLC detection and separation,the purity of the yellow pigment was80.15%.The yellow pigment of Epicoccum nigrum YL01 had the structure of esters,aromatic amines and triterpenoids.The stability of yellow pigment was analyzed.When stored in the dark for 36 hours,the preservation rate of the yellow pigment was96.69%;when the cumulative exposure to sunlight was 36 hours,the preservation rate of the yellow pigment was 76.61%.When stored for 48 hours in an environment with pH 1,7,and 13,the storage rates of yellow pigment were 19.17%,94.53%,and98.69%respectively;under alkaline conditions,there was a color-increasing effect,and when the p H was less than 7,the color fade was obvious.The yellow pigment was stored at 10 and 90?for 300 min,and the preservation rates were 99.40% and 85.52%,respectively.It has good stability in Ca²⁺,Zn²⁺,Mn²⁺and K⁺,and was easily destroyed in Fe²⁺and Fe³⁺;it had poor stability in strong oxidants and reducingagents.