Study On Diversity Of Lactic Acid Bacteria In Silage Fermentation

In this paper, we use the laboratory-made bag silage and silage samples in different regions, employing PCR-DGGE technology and traditional pure culture technology, comparing corn silage and alfalfa silage fermentation process of dynamic changes in flora diversity, and study the diversity of different surface areas of raw materials attached bacteria silage and silage more than half a year. And we come to the following conclusions.1. Research of corn silage and alfalfa silage in the diversity of lactic acid bacteria.pH value of corn silage reduced rapidly to the end of the experiment, and silage of the nutrition indicators all got to quality indicators. pH value of alfalfa silage and was maintained at above 5.5, and the rest of the nutrition indicators all got to quality indicators.We use bacterial universal primers V3 area expansion of corn silage and alfalfa silage microbial 16S rDNA and find by DGGE analysis of the product, corn silage and alfalfa silage fermentation with different advantages strips; Among them, ?-Acinetobacter,?-Pantoea,?-Escherichia,?-Lactococcus,?-Weissella koreensis,?-Enterobacter and other types of bacteria have been active in the silage; ? -Streptococcus,?-Endophytic,?-Enterobacter and other types of bacteria disappeare from the corn silage system 7days later. And some bands (cloning was not successful) of alfalfa silage in the late light became gradually dominated.LAB using bacterial universal primer amplification type of corn silage and alfalfa silage in the total microbial 16S rDNA, product analysis by DGGE, fermentation process in silage-Lactobacillus category was the most, followed by?-Lactococcus, and? Class-Weissella。There was trend that Lactobacillus brevis,?–Acetobacter,?- Leuconostoc corn silage in the gradual disappeared after 7days. Several Strains of bacteria were in the existence of alfalfa silage, and there are no significant change. Bacillus strains as a start was found in corn and alfalfa silage fermentation system, and in silage before (0 days) and silage at different time points, and it had a bright strip.After the use of traditional techniques of pure culture of corn silage and alfalfa silage lactic acid bacteria at different time points were isolated and identified, 118 were found, of which 57 bacilli, cocci 61. These bacteria appeared in the two materials, respectively, and in various time of the LAB isolated from different bacteria in the early majority, but as time silage fermentation, silage types of LAB cocci by the beginning of a gradual succession as Bacillus.2. Research of the diversity of materials attached to different parts of silage and silage strains of lactic acid bacteriaSilage in different regions of the raw materials and silage significant differences in nutrient composition, the product of silage fermentation was significantly higher, in line with the quality of raw materials after the silage fermentation requirements.The use of common areas of bacterial V3 amplified different regions of the surface material attached bacteria silage and silage microbial 16S rDNA, the product analysis by DGGE is as followed, the same surface area of raw materials silage bacteria attached to the type of similarity is relatively high, up to 93%, at least more than 80%; Plant surface attachment for silage fermentation bacteria unrelated to "bacteria", less LAB type, only found Lactococcus lactis subsp. Cremoris, Weissella koreennsis, Lactobacillus buchneri three lactic acid bacteria. Silage in different parts of similar types of bacteria is not high, only around 60%. Containing the bacteria detected ?-Acinetobacter,?–Pantoea,? -Escherchia,?-Pseudomonas and other types of bacteria. We also detected?-Lactobacillus,?-Lactococcus, ?-Weissella and other types of bacteria. These bacteria are located in various regions of farm silage.The use of common areas of bacterial LAB amplified different regions of the surface material attached bacteria silage and silage microbial 16S rDNA, the product analysis by DGGE is as followed, the same surface area of raw materials silage bacteria attached to the type of similarity was relatively low, up to only 75%, similarity of the same area was relatively high, both in the 63-94% between. LAB using the universal primer amplification type found most of the LAB, as well as bacteria-based, less cocci; among them Weissella confuse, Lactbacillus brevis, Acetobacter ghanensis, Lactococcus lactis, Weissella hellenica, Lactobacillus plantarum were found in 9 farms. Silage in different parts of lactic acid bacteria found by the cluster analysis of nine similar farm was not high, between 67% and 90%. More than half a year to the silo in the main group were ?-Lactobacillus ,and there are Lactococcus,Weissella,Leuconostoc in silage .The use of pure culture techniques in different regions of more than half a year of raw materials and silage analysis in identification of LAB, silage materials in different regions of the surface of a total of 69 lactic acid bacteria isolated, of which 40 were Lactobacillus, 29 were cocci. Lactic acid bacteria were different in difference regions, and plants in the same area with the surface of the lactic acid bacteria with high similarity. in the fermentation of silage 46 of more than half a year lactic acid bacteria were isolated. Lactobacillus were regional different between different types of large, and a regional three of the similarity between the farm was also low.Traditional pure culture method and PCR-DGGE conclusions do not correspond exactly. The traditional culture trains LAB selectively, and DGGE can better reflect the real structure of microbial fermentation system.