Study On Technique With Improving Feed Quality Of Soybean Meal By Biological Modified

Soybean meal was one of the high-grade vegetable protein. Its resource and nutrition was rich. More and more attentions was paid to the high utilization of soybean meal, but there were all kinds of anti-nutrition factors in soybean meal which greatly influence its feeding value and availability. Trypsin inhibitors (TI) which may lead to detrimental effects on young animal's growth was the primary anti-nutritional factors in soybean meals. At present, there was more commonly method to remove anti-nutrition factors by multi-strain fermentation. The elimination effective of phytic acid, lipoxygenase and lectin was better by multi-strain fermentation, but the elimination effective of TI was not better. And the elimination of anti-nutritional factors was reported, while at the same time more conducive to the absorption of small peptides of animal research less. In this study, selected ordinary soybean meal was raw material, study on the effect of feeding quality of soybean meal by multi-strain fermentation, and then carried out on the better bacteria to deal with nitrogen ion beam mutagenesis, screening mutation bacteria of efficient degradation of TI and significantly increased small peptide content. With a view to exploring a meal to improve the feeding quality by biological method.Experiment 1: The effect of feeding quality of soybean meal with mutil-strain fermentation. Selected ordinary soybean meal as raw material and Laobacillus plantarum, Bacillus subtilis, Bacillus cereus and Saccharomyces cerevisiae to studied on the effect of different levels inoculation, ventilation, the ratio of material and water and the fermentation temperature on TI and small peptide content in soybean meal by six groups of dual-mixed and four groups of ternary-mixed L9 (34) orthogonal experimental design. It showed that, in dual-mixed fermentation, the best combination of elimination TI was Bacillus subtilis and Saccharomyces cerevisiae , TI content decreases 25.89 mg/g in the inoculation 6 % , the ratio of material and water 1:1, the fermentation temperature 40℃, the ventilation 60 g/500mL after 48 h; and the best combination of elevation small peptide content was Laobacillus plantarum and Bacillus subtilis, small peptide content can up to 13.32 % in the inoculation 4 % , the ratio of material and water 1:1.2, the fermentation temperature 40℃, the ventilation 60 g/500mL after 48h. In ternary-mixed fermentation, the best combination of elimination TI was Bacillus subtilis,Bacillus cereus and Saccharomyces cerevisiae, TI content decreases 28.63 mg/g in the inoculation 4 %, the ratio of material and water 1:1.2, the fermentation temperature 40℃, the ventilation 45 g/500mL after 48 h; and the best combination of elevation small peptide content is Laobacillus plantarum, Bacillus subtilis and Bacillus cereus, small peptide content can up to 9.05 % in the inoculation 4 %, the ratio of material and water 1:1.2, the fermentation temperature 40℃, the ventilation 60 g/500mL after 48 h. The results suggest that the dual-mixed fermentation was better than the ternary-mixed fermentation, regardless of TI in the degradation or small peptide content increase. The degradation ability of TI with Bacillus subtilis was prominent in mixed fermentation.Experiment 2: Study on breeding of high-performance-degrading TI bacteria by N+ implantation. Selected Bacillus subtitles as original strains, N+ implantation energy chosen as 15 keV, dose five gradient settings were: 0.5,1.0,1.5, 2.0,2.5×1015 ions/cm2, with alkaline protease indicators for breeding. It showed that, in energy as 15 keV, the survival rate was decreasing with the N+ implantation dose increases, the survival rate gradually picked up when dose in 1.0×1015 ions/cm2～1.5×1015 ions/cm2, then the survival rate gradually lower. The curve was a typical "saddle-shaped" dose - effect curve. But the positive mutation rate was gradual upward trend. It can up to 16.8% when dose in 1.5×1015 ions/cm2, then gradually lower. The result showed the optimization parameters as : energy 15 keV , dose range of ion implantation 1.5×1015 ions/cm2. Mutant strains GA103 and GA301 of high-producing alkaline protease was breeding under this condition. By multiple screenings, mutation strain GC301-4-1 which producing alkaline protease activity was improved from 21.39 U/mL to 106.96 U/mL.Experiment 3: The optimization of solid-state fermentation conditions with mutation strain GA103 and GA301. Selected ordinary soybean meal as raw material and mutation strain GA103 and GA301 to study the effect of different fermentation conditions on TI and small peptide content in soybean meal by two groups of L16 (45) orthogonal experimental design. The result showed, the optimal fermentation condition of mutation strain GA103 were the inoculation 15 %, the ratio of material and water 1:1, the fermentation temperature 40℃, the fermentation time 96 h, the ventilation 60 g/500mL, pH nature. TI content decreases to 23.79 mg/g, the degradation rate can up to 40.02 %, the content of small peptide is 8.14 % under these conditions. The optimal fermentation condition of mutation strain GA301 were the inoculation 15 %, the ratio of material and water 1:1.2, the fermentation temperature 40℃, the fermentation time 96 h, the ventilation 75 g/500mL, pH nature. TI content decreases to 21.58 mg/g, the degradation rate can up to 47 %, the content of small peptide was 7.49 % under these conditions.Experiment 4:The effect of feeding quality of soybean meal with mutil-strain solid-state fermentation of mutation strain. Selected ordinary soybean meal as raw material and Laobacillus plantarum, GC301-4-1, Bacillus cereus, Saccharomyces cerevisiae to mutil-strain fermentation, the test group; Laobacillus plantarum, Bacillus subtilis, Bacillus cereus and Saccharomyces cerevisiae to mutil-strain fermentation, the control group; determination of fermentation results of 24 h, 48 h, 72 h and 96 h . Ratio of inoculation quantity of Bacillus subtilis :Bacillus cereus : Laobacillus plantarum :Saccharomyces cerevisiae =6 %:4%:4%:4%,the ratio of material and water 1:1, the fermentation temperature 37℃, pH nature to study the effects of mutil-strain fermentation before and after mutagenesis of Bacillus subtilis. The degradation effectiveness of TI and increase the content of small peptides as the main indicators. The result showed,in the test group, TI content decreases from 39.58 mg/g to 7.37 mg/g, degradation rate can up to 81.38 % , than 55.53 % of the control group increased 46.55%. The content of small peptide can up to 12.21 %, than 11.19 % of the control group increased 9.11 %.