Study On Production Of Corn Protein Feed By Solid State Fermentation Of DDGS

Distillers dried grains with soluble (DDGS) is co-product of alcohol production, it is one of the China’s staple agricultural resources. However, due to DDGS contains large amount of crude fiber and poor quality crude protein, it can not satisfy the nutritional demand of livestock, such as pigs and chickens. So, it is necessary to optimize the nutrition of DDGS to increase its feeding value.In this study, solid state fermentation technology was used to increase nutritional value and decrease the content of antinutritional factors of DDGS. Meanwhile, the wheat bran and cotton seed cake were added to the medium to reduce the cost of fermentation, and the fermentation technology parameters of the mixed medium were optimized as well.We used a strain of yeast named Pc1which was screened from our laboratory as one of the fermentation strain. We also screened a strain of mould, named HQII, which had the highest cellulose activity. DDGS was fermented using Pc1, HQⅡ and the Bs11(Bacillus subtilis) which was preserved in our lab together as the solid state fermentation strains.Based on the result of single factor fermentation experiment, we conducted the orthogonal (34) experiment. From the experiment, we concluded the best parameters for DDGS fermentation:urea additional proportion was0.03%, inoculation proportion was HQII:Pc1:Bs11=1:1:2, temperature was31℃, inoculation quantity was4%, the ratio of material to water was1:1, and fermentation time was48h. The crude protein content of DDGS fermentation product increased from17.34%to20.25%.In order to reduce the cost of DDGS fermentation medium, we adjusted the medium. And then we optimized the fermentation conditions of the mixed culture medium. The result showed that the best fermentation conditions were as followed:temperature was29℃, inoculation quantity was6%, the ratio of material to water was1:1, and the fermentation time was51h. The crude protein content of the fermentation product increased from19.83%to23.21%through fermentation。The safety of the fermentation product was detected. It was desmonstrated that the fermentation product did not contain Salmonella and urea residue.