Study On Optimization Process Of Multi-strain Fermented Soybean Meal

Fermented feed is a hot topic at present.Fermented soybean meal is one of them,and has many advantages compared with traditional soybean meal.Liquid fermentation is an important production method in enterprises.However,after the liquid fermentation is completed,after the extraction of the bacterias,the treatment of the fermentation liquid under the great environmental pressure has become an urgent problem to be solved.After the probiotics from liquid fermentationis is obtained by centrifugation,the remaining centrifugation liquid not only has residual bacteria,but also contains other substances which is beneficial to the growth of the animals.Fermented soybean meal can be produced with the centrifugal fluid which was originally discharged into the environment in a low energy-wasting and rational way.The optimum fermentation conditions for single-liquid was obtained.The four fermentation factors of fermentation temperature,inoculum size,ratio of material to water,and fermentation time was set.Single factor tests were carried out on the Four factors in different levels.Based on the results obtained by the single factor test,a four-factor three-level L₉?3⁴?test was conducted.The results showed that the optimum fermentation conditions for Bacillus liquid were:fermentation temperature 32?,inoculum volume 20%,ratio of material to water 1:09,fermentation time 60h.Under this condition,the activity of neutral protease of the obtained fermented soybean meal was 239 U/g,the activity value of alkaline protease was 128 U/g,the sum was 367 U/g,and the content of acid-soluble protein was 12.33%.The optimal fermentation conditions for the yeast centrifugation:fermentation temperature 28?,inoculum 25%,ratio of material to water 1:0.8,fermentation time60h.Under this condition,the obtained fermented soybean meal had an acid-soluble protein content of 3.32%and a total acid content of 5.73%.The optimal fermentation conditions for lactic acid bacteria liquid:fermentation temperature 28?,inoculum 15%,ratio of material to water 1:09,fermentation time 60h.Under this condition,the acid-soluble protein content was 6.84%and the total acid content was 6.44%.Based on the previous experiments,the effects of different ratios of the two kinds of liquid on the fermented soybean meal were explored.The fermentation temperature was30?,ratio of material to water was 1:0.9,the fermentation time was 72 h,and the inoculum amount was 20%.Set the addition ratio to 3:2,2:1,3:1,1:1,1:3,1:2,and 2:3.The test results show that when the Bacillus subtilis centrifugation solution is combined with the yeast centrifugation solution,the optimal addition ratio is 2:3.When Bacillus subtilis centrifugation is combined with lactic acid bacteria centrifugation,the optimal addition ratio is 1:2.When yeast yeast is combined with lactic acid bacteria centrifugation,the optimal addition ratio is 2:1.When the three fermentation centrates are combined,set the ratio of Bacillus:yeast:lactic acid bacteria=1:1:1,1:2:1,1:2:2,1:2:3,1:3:2.The optimal ratio is1:2:1.Each group of fermented soybean meal was analyzed for antigen protein degradation.The fermented soybean meal groups and the unfermented soybean meal were compared.The results showed that when the centrifugation of the three bacteria was combined to ferment soybean meal,the antigen protein degradation effect was the best.The analysis of nutrient composition of soybean meal in each group showed that Crude protein content and crude ash content of fermented soybean meal increased compared with unfermented soybean meal while the fiber content reduced.