Study Of The Fermentation Process Of Protein Feed By Distiller’s Grains With Multi-microorganisms

China has abundant resources of distiller’s grains but a shortage of protein resources.It is an effective way to make it fermented as protein feed.It is not only recycling the waste,but also reduces the environment pollution.In this paper,the protein feed was researched by drying and grinding distillers grains as raw materials,and using three kind of strain Candida utilis Y5a,Bacillus subtilis R5and Rhizopus oryzae W3.The main results are as follows:（1）The optimization of the culture media and cultivation condition was obtained by the three kind of microorganisms.The medium formula for producing the mixed inoculants was determined by response surface,PB experiments,climbing experiments and the center of rotation design experiments,as follows:wheat bran of 19.5 g,soybean meal of 10.5 g,sucrose of 0.74 g,NH₄Cl of 0.3 g,MgSO₄ of0.15 g,NaCl of 0.18 g,KH₂PO₄ of 0.21 g,MnSO₄ of 0.06 g.The cultivation conditions were studied by a single factor as:the inoculum of C utilis Y5a,B subtilis R5,R.oryzae W3 of 5%,an initial water content for solid culture medium of 50%,fermentation time of 52 h,fermention temperature of around30℃.（2）The effect of dealing with mixed enzymes and R oryzae W3 on degrading crude fiber was researched.The optimal ratio was determined by orthogonal test as this:cellulase enzyme 3%,β-glucanase 1%,xylanase 2%.The optimum degradation conditions by mixed enzymes were pH 4.5,initial moisture content 50%,treatment temperature 45℃,the processing time 22 h.The radio of crude fiber of distillers grains by enzyme treatment was 18.97%,19.04%less than before.Inoculating the strain W3 to distillers grains firstly,and fermenting for 8 d,the content of crude fiber was 17.61%decreased 27.01%compared with the previous.After treating by the mixed enzyme for 1 d and then fermenting for 7d by R.oryzae W3 at distillers grains,crude fiber content was droped down to 13.36%,reduced 42.98%compared wiht the pre-treatment method.（3）The optimized fermentation conditions were achieved by fermenting distillers grains in barrels with mixed microbial inoculum,which was an initial water content of 40%,an initial pH of 5.5,fermentation time 5 d,and the crude protein content was 26.74%,increased 48.83%more than the previous fermentation.Through the method of fermenting distillers grains for 7 d firstly by R.oryzae W3 and cultivating them for 4 d with the two strains of Candida utilis Y5a and Bacillus subtilis R5,the content of raw protein and rule protein were 29.13%and 22.43%respectively,increased 62.01%and76.34%compared to before,and crude fiber content was 12.37%,reduced 47.20%compared with pre-fermentation distillers grains.The color and smell of the protein feed was good.