Isolation And Screening Of Excellent Lactic Acid Bacteria For Silage And Preliminary Application Effect

【Objective】For the study of the lactic acid bacteria impacting of the fermentation quality and aerobicstability of silage, this test isolated and filtered out the good lactobacillus from silage, then made it asadditives which added to the whole-plant corn, thus determing the sample nutrients and aerobic stability ofsilage and aerobic after exposure. It provided the theoretical guidance for the development of new inoculantproducts and reasonable selection of inoculant production, as well as the theoretical basis for the process ofsilage fermentation and aerobic stability.【Methods】(1) The lactic acid bacteria isolated from silage samples by plate separation, then identificationthrough bacterial morphological characteristics, physiological and biochemical characteristics and acombination of methods for16S rRNA gene sequence analysis. The used of production of acid testantibacterial test, the test of cellulase production from lactic acid bacteria isolated Filter silage potential oflactic acid bacteria measured filter out the lactic acid bacteria, the growth curve, temperature sensitivity, acidresistance, salt tolerance, more screening lactic acid bacteria in the biological characteristics and resistance,determine the excellent for silage lactic acid bacteria.(2) Filtered out the good lactic acid bacteria into singleagents or composition of flora which add to corn stalks, then put into the polyethylene bag of vacuum sealedsilage. Sampled during silage7,15and30d, and silage bag opening1,3,7,15and30d, to explore silage andaerobic microbial dynamics in the exposure process with the total number of bacteria in the samples, the totalnumber of lactic acid bacteria, total number of yeast, the total number of fungal statistical by spread platemethod. Meanwhile determining the pH value, NH3-N, LA, AA, PA, BA, DM, NDF, ADF, CP, the WSCcontent of each of said points,obtained the dynamic changes in the various stages of microorganisms andnutrients related eventually filter out the best for straw silage inoculants.【Results】(1)The Blast analysis of the16sRNA gene of the lactic acid bacteria isolates in Genbank,thehomology reaches99%with the corresponding reference strains.(2) Production of acid test: the fastest acidproduction of the strain was B2-8,followed by B3-1,B1-6, B1-3, B2-9, B4-5, the acid production of strainB1-7, B2-3, B2-7, B5-1, B5-2, B6-1, B7-1, B7-10, E2-3were relatively slow, but the pH reduced to4or lessafter20h showing better acid-producing properties. Antibacterial test: the supernatant of lactic acid bacteriaisolates had no inhibitory effect on the test mold. strain B3-1inhibitory spectrum contained antibacterialactivity and width, strain B2-3and B2-8followed by strain B1-6,B1-7,B2-7, B5-1, B5-2only to inhibitionthe Staphylococcus aureus. Cellulase production screening test: all isolates are not cellulase production.(3)The number of lactic acid bacteria of silage in each group reached the maximum in the first day, thengradually reduced. The number of each experimental group was significantly more than the control group (P＜0.05); It continued to reduce the number of the group of lactic acid bacteria, but the number of lactic acidbacteria of each test group significantly more than the control group (P＜0.05) during aerobic exposure period. The number of Yeasts, molds rapid growth early in the silage, reaches the maximum after3d, thenreduced down to100CFU/g during15and7d respectively,; Aerobic exposure of each group of yeasts andmolds gradual increased in the number of corruption in each experimental group.The number ofmicroorganisms was significantly lower than the control group (P＜0.05).(4) The pH,WSC, NH3-N of eachexperimental group were significantly lower than the control group (P＜0.05) during silage and aerobicexposure, the DM, CP, NDF, ADF, LA, AA content of the each test group were significantly higher than thatin the control group (P＜0.05), PA and BA were not tested during experiment.【Conclusions】(1) Successfully isolated32strains of lactic acid bacteria, including21bacilli,11cocci.Lactobacillus plantarum identified4,17Lactobacillus fermentum,5Enterococcus feces,1Leuconostocmesenteroides subsp. Mesenteroides and5lactose Pediococcus.(2) B1-6, B1-7, B2-3, B2-8, B3-1, B5-2,B7-10, E2-3showed a preferred acid-producing ability and antibacterial ability which had a good potential ofsilage. Eventually the B1-7, B2-3, B3-1, B5-2, E2-3were selected from laboratory silage determined by theirbiological characteristics,(3) All mixed group of lactic acid bacteria, the mixed group of homotype lactic acidbacteria and B3-1group of Lactobacillus plantarum with great potential in improving the quality and aerobicstability of silage fermentation.