Isolation And Screening Of Cellulose-degrading Microorganism And Its Effect On Utilization Of Ammoniated Wheat Straw And Corn Stalk

In this study,wheat straw and corn stalk were used as raw materials,aiming to determine the effect of cellulolytic bacteria on the utilization of ammoniated straw with a completely randomized block design.This study consisted of the following three experiments:Experiment 1: Isolation and Screening of of cellulose-degrading microorganism.In this experiment,under the conditions of p H 4.5,6.8 and 9.5,according to the size of the circle zone formed on the Congo red medium and the cellulase activity,seven strains of cellulose-degrading microorganism were isolated and identified from the intestines of the locusts,moldy trees,rhinoceros,elephants and giraffe feces.Then,we studied its molecular biology identification.We find that S26,Y29,X67,C72,S87,D100 and X107 was Brevibacterium halctolerans,Bacillus subtilis,Bacillus subtilis,Exiguobacterium aurantiacum,Bacillus pumilus,Bacillus pumilus and Bacillus pumilus,respectively.Experiment 2: The effect of adding cellulose-degrading microorganism on the utilization of ammoniated straw.Experiment 2: We desinged two treatments: without cellulose-degrading microorganism(Control)and cellulose-degrading microorganism addition group.Wheat Straw and Corn Stalk was ammoniated for 15 days,and cellulose-degrading microorganism were added to the ammoniated straw storage for 7 days,14 days and 21 days.Samples were collected and the chemical composition of the straw was measured.The results showed: compared with the untreated ammoniated wheat straw,the addition of S26,Y29 and S87 was effective at 7 days,increasing the WSC content by 27%~32%,decreasing the NDF content by3.6~4.8% and the ADF content by 7.1%~7.8%,and the cellullose content by 10.2% to 14.8%.Compared with the untreated ammoniated corn stover,the addition of S87 was effective at 7 days,decreasing the WSC content by 30.9%,The content of cellulose and hemicellulose was on the rise,decreasing the ADL content by 41.1%.Experiemnt 3: The effect of adding cellulose-degrading microorganism on the in vitro fermentation characteristics of ammoniated strawThe control group and the cellulose-degrading microorganism addition group in experiment 2 were used to in vitro rumen fermentation test.At the end of 48 h,gas samples,liquid samples and nylon bag samples were collected and determined total gas production,methane production,the content of VFA,cellulase activity,ammonia nitrogen and the population of ruminal bacterial.The results showed that the activity of ?-glycosidase and pectinase of ammoniated wheat straw with cellulose-degrading microorganism was higher than that of the untreated ammoniated group(P < 0.05).The activity of Carboxymethyl Cellulase and pectinase of corn stover with cellulose-degrading microorganism addition was higher than that of the ammoniated group(P < 0.05).Compared the untreated ammoniated wheat straw,the addition of S26,Y29 and S87 increased the gas production and methane production by about 2 times;DM-D increased by about 14.8%,NDF-D by 32.5%;VFA by about 18.5%.Compared the untreated ammoniated corn stover,the addition of S87 increased the gas yield by 22.9%,DM-D increased by about7.1%,NDF-D by 8.3%,VFA by 20.6%.In conclusion,considering the effect of cellulolytic bacteria on the the nutritional value and rumen fermentation of ammoniated straw,Y29(Bacillus subtilis)screened in this experiment can improve the ammonia utilization of wheat straw,and S87(Bacillus pumilus)can increase ammoniated corn stover.