Study On Enrichment Culture Of Feed Mixed Bacteria And Freeze Drying Process

Feeding lactic acid bacteria is a kind of directly added to the silage fermentation agent in green feed,because it contains a lot of lactic acid bacteria have strong acid producing ability,lactic acid bacteria can rapidly reduce the pH values of silage and can effective suppression of harmful bacteria breeding and can improve the quality of Silage,but lactic acid bacteria cannot use the cellulose,it is impossible to improve silage digestibility and reduce the utilization rate of feed;so far,The main method to improve the digestibility of silage at home and abroad is adding mixture of cellulose decomposing enzyme and lactic acid bacteria at silage fermentation process, The cellulose decomposing enzyme able to decomposition the Plant cell wall, which makes the decreased the fiber content of plants and provide more carbohydrates for lactic acid bacteria and promote the quality of silage fermentation and improve the digestibility of animal feed and production performance, effectively improve the nutritive value of Silage and can prolong preservation period..but In the production of silage The temperature of fermentation has been increased to more than 60 ℃make cellulose enzyme denatured inactivation, so the silage fermentation quality and digestion rate was affected. In addition, in silage field production requires a lot of cellulose decomposing enzyme, the preparation is complex,the cost is relatively high and repeat utilization is low.In recent years, the research of experimental results that lactic acid bacteria that screening has a advantage about a growth range is wide and acid, acid producing ability is strong.Cellulose decomposing bacteria also has a advantage about growth range is wide and acid and cellulose decomposing ability is strong.mixed culture that there is no mutual effects between two bacteria,this will provide a scientific basis for the research and development of mixed bacteria feed additive.study on mixed bacteria additive in a liquid state yet.In the actual production needs large amount of bacteria suspension,the transportation and preservation of the bacterial suspension is not convenient,therefore, the research and development of mixed bacteria powder feed additives have a economic and social significance about reduce the cost of highquality silage production and To improve the fermentation quality and digestibility and alleviate the shortage of feed.In this paper, the selected lactic acid bacteria(A4+A7) and cellulose decomposing bacteria(Nf+Y6) is experimental strain. the mixed bacteria culture medium optimization and Mixed bacteria enrichment culture,mixed bacteria freeze-drying process and optimize the complex water conditions is the experimental object, in order to research the technical route and Industrial parameters of Lactic acid bacteria and cellulose decomposing bacteria feed mixed bacteria freeze-dried powder preparation, to provide theoretical foundation for the industrial production of silage freeze-dried powder mixed bacteria additive.1.The lactic acid bacteria(A4+A7, isolated from corn straw) and cellulose decomposing bacteria(Nf+Y6, isolated from cattle, sheep rumen) enrichment results: different treatment groups in two strains with the same proportion(A4+A7:Nf+Y6=1:1) mixed culture in 2% sucrose(urea + salt solution: =2.0%:1.0%). Steady stage the shortest time, 12 h entered a stable period, the highest number of live bacteria, living bacteria number is 4.49 * 109cfu/ml;(mixed bacteria in 2% sucrose solution when cultured living bacteria number is 1.62 * 108cfu/ml).2.Using centrifugal separation method centrifugal for mixed bacteria, result shows that under the condition of the centrifugal force is 4000 g, centrifugal rotational speed is 5000 r / min,centrifugal temperature is 20℃, centrifugal time for 15 min, the forage mixed bacteria centrifugal effect is best, the survival rate of centrifugal is 88.9% and almost no bacteria residue in the supernatant.3. The mixed sediment bacteria that through centrifugal separation method were isolated are Separate mixed With eight kinds of protective agent, pre-reezing process under different low temperature conditions, pre-freezing results that Mixed bacteria have a highest survival rate when the temperature is-20 ℃; mixed bacteria sediment are mixed with different freeze drying protective agent, Results it is concluded that when the best composite freeze-dried protectant formula of mixed bacteria is 10% skim milk, 2% ascorbic acid, 6% trehalose, glucose 1%,and freeze-drying thickness is 0.5cm, at this moment the freeze-dried survival rate is highest, Can beup to 87.92%; After freeze-dried the powder of freeze-dried mixed bacteria are mixed with Water preparation according to the proportion of 10:1.0 and to measure the survival rate, the results showed that the best water preparation of powder of freeze-dried mixed bacteria is 12% skimmed milk; when 12% skimmed milk is mixed with powder of freeze-dried mixed bacteria according to the proportion of 1.0:10 and rewatering 15 min at the temperature of 25 ℃ have a highest Mixed bacteria survival rate, can be up to 88.79%.