Evaluation Of The Microbial Diversity Of Traditional Fermented Vegetables In Jilin, Guizhou And Their Antioxidant Function Of Lactic Acid Bacteria

Fermented vegetables as an important part in fermented foods in our country,because of its fragrance,entrance crisp,rich nutrition and was deeply loved by people,this topic mainly in guizhou,jilin two representative fermented vegetables conducted microscopic community and diversity were analyzed,and at the same time of lactic acid bacteria strains isolated in vitro antioxidant activity evaluation,the main results were as follows:1.The results of 16 S ampli metagenomic analysis showed that Firmicutes and Proteobacteria were the absolute dominant phyla at the phylum level of fermented vegetables in Guizhou,with the sum of abundance greater than 85%.At the family level,the dominant family was Lactobacillaceae,followed by Sphingomonas family,Acidobacteriaceae,Prevotella family,Neisseriaceae,with the sum of relative abundance greater than 80%.At the genus level,the dominant bacteria were Lactobacillus,Sphingolomonas,Neosphingolomonas and Prevotella.At the species level,the dominant strains were Lactobacillus denderi,Lactobacillus brevis,Neisseria flava,and Rosomyces slime.Firmicutes,Proteobacteria,Cyanobacteria,Bacteroidetes,Fusobacteria,Actinobacteria had great changes in the abundance of fermented vegetables in Guizhou.At the family level,they were Lactobacillaceae,Sphingomonas,Enterobacteriaceae and Acidobacteriaceae.At the genus level,the abundance of Lactobacillus,Neosphingolipides,Sphingomonas and Prevotella varied greatly in each sample.At the species level,the abundance of Lactobacillus denderi,Lactobacillus brevis,Prevotella melanogenes,Neisseria flava,Rosomycetes slime and Lactobacillus food-like varied greatly in each sample.2.The results of 16 S ampli metagenomic analysis showed that Firmicutes,Proteobacteria and Cyanobacteria were the dominant bacteria at the phylum level,and their total abundance was more than 90%.At the level of families,the abundance of Leuconiaceae was the highest,followed by Lactobacillaceae,Enterobacteriaceae and Streptococcaceae.At the genus level,Lactobacillus,Leuconostoc,Lactobacillus,Acinetobacter,Neospermitis,Fusobacteria,Streptococcus,Neisseria and Prevotella were the main bacteria,and their total abundance was more than 90%.At the species level,Lactobacillus brevis,Erwinella,Lactobacillus food,Rossiella slime,and Neisseria flaviensis were the dominant strains.Firmicutes,Proteobacteria,Cyanobacteria,Bacteroidetes,Fusobacteria,Actinobacteria were the most abundant bacteria in fermented vegetables from Jilin Province.At the family level were Lactobacillaceae,Leuconoidaceae,Sphingomonas,Enterobacteriaceae,Acidobacteriaceae,Streptococcus,Prevotella,Neisseriaceae,Stoneobacteriaceae,Fusobacteriaceae;At the genus level,the main species were Lactobacillus,Leuconostoc,Streptococcus,Lactobacillus,Orwinella,Bacteroidetes,and Stonybacterium.At the species level,they were mainly Lactobacillus brevis,Prevotella melanogenes,Neisseria flaviensis,Rosomycetes slime,Lactobacillus food-like,etc.3.According to Veen diagram and Alpha diversity analysis,the species richness and diversity of Jilin Group were lower than those of Guizhou Group.Stamp and LEFSE analysis showed that the abundance of bacteria in Jilin Group and Guizhou Group was significantly different at the genus level,with 20 genera and 18 genera,respectively.4.Through Picrust analysis,the major functional gene categories predicted by COG in the two groups were basically the same,but their abundances were different.The results of KEGG function prediction showed that in the two groups of samples,the primary function was mainly related to metabolism,and the abundance of related genes reached 43.44%～52.53%.The secondary function was mainly related to membrane transporter enzyme family,energy metabolism,cell process and signal transduction,and the biosynthesis of secondary metabolites.5.A total of 41 strains of lactobacillus were isolated from the samples from Jilin Province by traditional methods,including 6 strains of Lactobacillus plantarum,16 strains of Lactobacillus brevis,9 strains of Lactobacillus sakes,2 strains of Lactobacillus Korea,5 strains of C.pseudoenterovii,and 3 strains of Weissella virifolia.A total of 26 strains of lactobacillus were isolated from Guizhou samples,including 5 strains of Lactobacillus plantarum,13 strains of Lactobacillus brucellosis,3 strains of Lactobacillus acidophilus and 1 strain of Lactobacillus paracasei.The results of α diversity analysis of Lactobacillus strains isolated from Jilin group and Guizhou group showed that the diversity and richness of Lactobacillus strains isolated from Guizhou group were higher than those from Jilin group.Phylogenetic trees were constructed by using MegaX software for the isolates from Jilin and Guizhou,and it was found that there was no regional evolutionary relationship between the isolates from these two regions.6.Four methods of in vitro antioxidant activity assessment were used to evaluate the antioxidant function of the isolated lactic acid bacteria strains.The results showed that the fermentation supernatant of 55 strains had high ABTS free radical scavenging ability,and the scavenging rate ranged from 86.02% to 92.81%.The results showed that the fermentation supernatant of 55 strains had high ABTS free radical scavenging ability.The ABTS free radical scavenging rates of intact cells of 46 strains of lactic acid bacteria ranged from 0.48% to 12.02%.The cell-free extracts of 50 strains of lactic acid bacteria were in the range of 0.66%～17.46%.The supernatant of Lactobacillus strain 59 had DPPH radical scavenging ability,and its scavenging rate ranged from 27.69% to73.15%.The DPPH radical scavenging ability of the intact cells of 29 strains of lactic acid bacteria ranged from 0.54% to 18%.The cell-free extracts of 28 lactic acid bacteria had DPPH free radical scavenging rates ranging from 0.27% to 20.78%.The anti-lipid peroxidation inhibition rates of 7strains of lactic acid bacteria fermentation superniter were 5.41%-18.33%,the anti-lipid peroxidation inhibition rates of 33 strains of intact cells of lactic acid bacteria were 1.66%-54.37%,and the anti-lipid peroxidation inhibition rates of 30 strains of cell-free extracts were 3.49%-81.39%.The ferric ion chelating ability test showed that the ferric ion chelating rate of the supernatant of 23 lactic acid bacteria strains ranged from 13.11% to 84.69%,and the ferric ion chelating rate of the intact cells of 24 lactic acid bacteria strains ranged from 45.65% to 96.4%.The chelation rates of the cell-free extracts of 39 lactic acid bacteria strains ranged from 58.87% to95.98%.In guizhou and jilin two groups of lactic acid bacteria,comparing the antioxidant capacity of the group of fermented supernatant for guizhou ABTS free radical clearance rate is greater than the jilin group,guizhou group fermentation supernatant and whole cells of DPPH free radical clearance rate is greater than the jilin group,and significant difference,two groups of lactic acid bacteria fermentation supernatant,whole cells,cell free extracts of lipid peroxide and ferrous ion chelating difference is not big.Conclusion:The microbial diversity of traditional fermented vegetables in Guizhou is higher than that in Jilin.There were great differences in families,genera and species of dominant microorganisms between the two regions.The dominant microorganism identified by traditional isolation method is not completely consistent with the dominant microflora obtained by 16 S ampliconmetagenomic analysis.The scavenging ability of extracellular extracts of lactic acid bacteria on ABTS free radical and DPPH was much higher than that of intact cells and intracellular extracts,and the anti-lipid peroxidation inhibition ability and ferrous ion chelation ability of extracellular extracts of lactic acid bacteria were lower than that of intact cells and extracellular extracts.The ABTS free radical scavenging ability and DPPH scavenging ability of intact lactic acid bacteria were not significantly different from that of intracellular extracts.The anti-lipid peroxidation inhibition ability and the chelating ability of the intact cells were lower than those of the intracellular extracts.The ability of ABTS free radical scavenging,DPPH free radical scavenging and anti-lipid peroxidation of lactic acid bacteria in Guizhou group was higher than that in Jilin group as a whole,and the ability of ferrous ion chelating of lactic acid bacteria in Jilin group was higher than that in Guizhou group as a whole.