Study On Solid-state Fermentation Parameters Of Liquor Grains Yeast Culture

Yeast culture is a kind of micro-ecological preparation with functions of nutrition and health care.It is rich in a variety of nutrients and some unknown growth factors,so it has been paid much attention to in animal husbandry at home and abroad.With the development of domestic animal husbandry and the high price of imported products,the research and development of yeast culture products is more and more popular in China.The annual output of liquor distiller’s grains in China is tens of millions of tons,the quantity is large and concentrated,the price is low,and the nutrition is rich,so it is widely used in feed industry.In order to reduce the production cost and optimize the nutrient composition of liquor distiller’s grains,this study studied the production technology of liquor distiller’s grains yeast culture by using liquor distiller’s grains as the fermentation matrix,Saccharomyces cerevisiae and Candida utilis as the fermentation strains,and using liquid and solid composite fermentation techniques.Firstly,the specific properties of fermentation strains were preliminarily identified,and then the conditions of liquid fermentation of yeast,the conditions of high-density solid-state fermentation based on liquor grains,the conditions of autolysis of yeast culture were optimized and studied,as well as the detection and comparison of yeast autolysis with the conventional components of liquor grains.The main test results are as follows:(1)Both Candida utilis and Saccharomyces cerevisiae have strong resistance to acid and high temperature.Candida can produce cellulase,lipase,protease and amylase,while saccharomyces cerevisiae does not produce amylase,but can produce cellulase,lipase and protease.(2)The fermentation parameters were determined as follows: in the preparation of fermentation broth,the inoculation amount of candida prion was 20%,the fermentation time was 24 h,and the temperature was 30℃.Saccharomyces cerevisiae inoculated 10%,fermentation time 30 h,temperature 30℃.The liquor grains were loaded with 30 g,the ratio of feed and water was 1:1,the inoculation amount of compound bacteria was 50%,the inoculation ratio of candida prion and Saccharomyces cerevisiae was 3:1,the addition amount of peptone was 0.5%,the addition amount of glucose was 2%,and the fermentation temperature was constant temperature at 30℃ under natural p H for 3d,the number of yeast per gram of culture could reach 4.5-5 billion.(3)The process of autolytic treatment of the fermentation culture under laboratory conditions is as follows: a certain amount of autolytic material is weighed to make the material-water ratio 0.75:1,3% sodium chloride is added,and the culture is cultured at 55 ℃for 48 hours.At this time,the content of amino acid nitrogen in each gram of autolytic liquor grains yeast culture was 10.32 mg.(4)The content of crude protein in yeast culture increased by 14.60%,the content of crude fiber decreased by 20.94%,the content of crude ash and calcium increased by 5.04%and 3.57% respectively,and the content of crude fat and phosphorus decreased by 2.16%and 6.45% respectively.