Bacterial Community Capable Of Corn Straw Degradation At Normal Temperature And Its Application In The Biological Bed Of The Calf

Wtih the rapid developing of dairy industry in recent years,more and more large-scale dairy farms appeared in China.And waste pollution has become a bottleneck in the development of dairy industry,it has become one of the hot spots in the dairy industry that how to reduce and deal with the sewage.In this study,we try to develop a new technology to solve the above problems.The combination of simulation test and field test,the composition and density of the material were selected and optimized,a set of bacterial community which can rapidly degrade ligncellulose at normal temperature were selected,and analysis of bacterial diversity in the bacterial community.Inoculating the biological bactria bed with the bacterial community as the inoculation agent,the diversity of bacterial community was analyzed by high throughput sequencing technology,the structure of bacterial community was analyzed.In the end,the main parameters of the technique for the culture of calves were proposed.The main results are as follows:1.The cellulose degradation rate was the main index,a series of high efficient cellulose degrading strains were obtained.The optimum cellulose decomposition temperature was 30 ℃and the optimum pH value was 8.0,and the degradation rate of filter paper and corn stalk were66.5% and 66.1%.The degradation rates of cellulose,hemicellulose and lignin were 32.0%,85.2% and 17.2%,respectively.The diversity of the bacterial composition of the bacterial community was analyzed by high throughput sequencing,the results showed that at the genus level,the bacterial community is mainly composed of Pseudomonas sp.,33.9%,Bacteroides sp.,11.8%,Acidovorax sp.,6.9%,Alcaligenes sp.,3.9%,Butyrivibrio sp.,1%,at the species level,the bacteria community were mainly composed of Alcallgenes-faecalis 2%,Microvirgula-aerodenitrificans 1.5%.2.Feeding density simulation test showed,there was no significant difference between the three simulated density settings(T1: head/2m2,head/1.5m2,T3 : head/1.5m2),the amount of ammonia in the T1 and the T2 was lower,and the feeding density was more preferred in these two groups.The simulation results show that the rice husk and sawdust are used as cushion material,it was good for sawdust as cushion material,because the temperature of sawdust3.treatment is higher than that of other components,the highest temperature reaches 39℃,and the ammonia emission of sawdust treatment is the lowest 1.456mg/L.Therefore,the choice of sawdust as the main component of the cushion material is preferred.4.The results of field feeding density test,test set of three density gradients(T1:head/1.6m2,head/1.5m2,T3:head/2m2,control group: head/1.8m2).During the test,the surface pH of the T3 was the highest,there was no significant difference between the deep pH,the change trend of water content in region is the same,and the water content of the T3 is the lowest,the temperature in the T3 was higher than in the other treatments,the maximum surface temperature of 32℃ is reached at 60 d,and the deep temperature reaches to the temperature of37℃,ammonia emissions in the T3 were higher than those in other treatments before 45 d,after45d,the ammonia emission was lower than that of other treatments,the control group was much higher than the treatments.The total nitrogen content in the treatment group was higher than that in the control group,the content of total organic carbon tended to be consistent but the total organic carbon in the T3 was higher than that in other treatments and showing a certain advantage,so the density of the T3 is the most appropriate.5.The analysis of bacterial diversity in field test,from the level of the phylum,the Proteobacteria as the dominant flora,the content of Proteobacteria was more than 35% at each test site,the second is the Bacteroidetes,in addition to the treatment of initial stage,the other test points were more than 27%,the highest content was up to 41.7%.There are many kinds of different species of genus in the mat,and different dominant strains will appear in different treatments.The microorganisms in the pad can breed bacteria which can degrade the feces accroding to the change of the flora,Paenibacillus sp.,Thauera sp.,Cellvibrio sp.,Pseudomonas sp.,etc.Based on the above experiments,the degradation ability and the diversity of bacterial composition were determined and applied it to the biological bacteria bed,at the same time,the the sawdust was selected as the cushion material to test the effect well,and the each calf was determined to cover an area of 2m2,which laid the foundation for the improvement and wide application of the technology.