Solid State Fermentation Of Yeast Culture Based On Yellow Wine Lees

As single cell protein feed, yeast culture’s excellent quality and good feeding value had attracted the attention of domestic and foreign breeding industry. With an annual output of 800000 tons, yellow wine lees was a valuable kind of reusable resources and rich in carbohydrates, proteins, amino acids and other substances, which, however, has not been fully developed and applied. Relevant experiments were conducted to investigate the biotransformation of yellow wine lees, which aimed at developing new protein feed and changing the waste into treasured gold. The main issues were as followed:state fermentation of saccharomyces cerevisiae, autolysis of yeast culture, then the final comparative analysis of the component between yellow wine lees and autolyzed yeast culture.The ingredients analysis showed that yellow wine lees contained a lot of starch and protein, which accounted for 38% and 36.14% respectively. Then it was crude fat which took 7.26% of raw material.While the amounts of reducing sugars and ash were 2.99% and 2.2%. The molecular weight of proteins in yellow wine lees were 972.39 Da, which were mainly small peptides accounted for 3.9%. The total content of free amino acids accounted for 3.65%, including eight essential amino acids which took 43.8% of the total free amino acids.The toxin content were as followed:OTA 33.25μg/kg; ZEN 214.15 μg/kg; AFB110.05 μg/kg; DON<222 μg/kg, they all met the standards.Based on studies of ingredients analysis, yeast state fermentation was discussed. The optimal fermentation process were as followed:the charge amount was 30 g, the inoculation amount was 90 million CFU/g, the ratio of water to material was 1:1, the supplementation amount of enzyme was 300 U/g, the supplementation amount of soluble starch was 2%, the supplementation amount of ammonium sulfate is 1%, incubated at natural pH value under 30 "C for 72 h and stirred up for every 12h. The final yeast amount of yeast culture can reach 35 to 40 billion per gram.Furthermore yeast culture autolysis was studied to determine the optimal autolysis conditions:loading capacity was 10 g, the ratio of material to water was 1:1.5, the supplementation amount of enzyme was 300 U/g, the supplementation amount of anhydrous ethanol was 3%, the supplementation amount of sodium chloride was 3%, autolyze at natural pH value under 45℃ for 48 h, the yield of amino acid nitrogen reached 14.93 mg/g.Finally, comparative analysis of the ingredient-changes between yellow wine lees and autolyzed yeast culture were achieved. Compared with the raw material, the soluble starch content of autolyzed yeast culture reduced by 25.86%, the reducing sugar content reached 10.89%, increased by 7.10%. The content of crude fiber was 4.60%, which decreased 0.20% comparing to raw materials. While in contrast to the soluble starch, the content of crude protein increased from 36.14% to 47.99%. The small peptide increased by 3.29%, of which the molecular weight was 1047.23-1750.42 Da. The content of free amino acids decreased from 3.65% to 3.45%, of which eight essential amino acids took 42.32%. The toxin content data had small amplitude fluctuations, but still accorded with the national standards.