| Traditional fermented soybean paste production was mainly divided into stages of meju and mashed.Meju quality is particularly important,it can provide abundant microorganisms for soybean paste,different microbial creates an unique flavor.At present,most add Aspergillus oryzae and Aspergillus Niger making the meju in the industry.However,a single strain make soybean paste fragrance,flavor and palatability is far less than the traditional fermented soybean paste.Therefore,explore microbial diversity in traditional fermented meju is very important to achieve the industrialization production of the traditional fermented soybean paste.In this study,traditional fermented meju from different regions and different fermentation stages in Liaoning province were analyzed by Illumina MiSeq sequencing technology;the protein function and microbial source were analyzed by metaproteomics technology,The results are as follows:1.A total of 1,696,670 reads and 747 OTUs in the bacteria and a total of 2,087,284 reads and 621 OTUs in the fungi were obtained from twenty-two natural fermented meju samples through Illumina MiSeq sequencing analysis.Natural fermented meju were detected five known bacteria at phylum,nineteen of twenty-two samples dominant bacteria was Firmicutes,two of twenty-two meju samples dominant bacteria was Prteobacteria.Three known fungi at phylum were detected in 22 meju sample.Nineteen of twenty-two meju samples dominant fungi was Ascomycota,Two of twenty-two meju samples dominant fungi was Zygomycota.At the level of genus,a total of 43 genus were detected,the dominant bacteria for Lactobacillus,Enterococcus,Fructobacillus,Staphylococcus,Carnobacterium,Leuconostoc and Bacillus.A total of 34 genus were detected,the dominant bacteria for Penicillium,Mucor,Fusarium,Aspergillus,Rhizopus.2.Natural fermented meju from Kaiyuan,Shenyang,Xinmin in Liaoning province at different fermentation stages of bacterial OTU were increased at first and then decreased,The highest OTU at fermentation 0 d,different fermentation stages of bacterial species abundance were increased at first and then decreased.Natural fermented meju at different fermentation stages of fungi OTU number change trend is not obvious.Natural fermented meju from Xinmin at different fermentation stages of dominant bacteria was Firmicutes,natural fermented meju from Kaiyuan and Shenyang at different fermentation stages of dominant bacteria was Proteobacteria.Natural fermented meju at different fermentation stages of dominant fungi was Ascomycota and Zygomycota.At the level of genus,natural fermented meju at different fermentation stages were detected bacterial 30 genus,including Lactobacillus,Enterococcus Leuconostoc Weissella in different fermentation stages meju sample were detected.Weissella was the dominant bacteria at fermentation 0 d in Kaiyuan,but Lactobacillus was the dominant bacteria at middle and later fermentation periods.The dominant bacteria for Other in the different fermentation stages meju sample in Shenyang,bacterial species more abundant during fermentation 40 d.The dominant bacteria for Enterococcus in the different fermentation stages meju sample in Xinmim.Natural fermented meju at different fermentation stages were detected fungi 17 genus,Penicillium and Mucor in different fermentation stages meju sample were detected.The dominant fungi for Mucor in the different fermentation stages meju sample in Kaiyuan.Penicillium was the dominant fungi at fermentation 0 d and 20 d in Shenyang,but Rhizopus was the dominant bacteria at middle and later fermentation periods.Penicillium was the dominant fungi at fermentation 0 d and 20 d in Xinmin,but Gibberella was the dominant bacteria at middle and later fermentation periods.3.A total of 1415 protein were identification through macro protein extraction and mass spectrum identification in the different fermentation stages meju sample in Shengyang,which is derived from the Rhizopus protein accounts for 15.7%of total protein and from penicillium protein accounted for 13.9%of total protein.The identification of 1415 proteins compared with COG proteins in the database,which identification to 12 classification including 1240 COG function classification.Involved in carbohydrate of transport and metabolism enzyme was 149,involved in amino acids of transport and metabolism enzyme was 41,involved in protein enzyme was 24,involved in nucleotide of transport and metabolism enzyme was 24,involved in coenzyme of transport and metabolism enzyme was 16,most of these enzymes were from Rhizopus,Penicillium and Yeast.In this study,our objective was to analyze the microbial community structures of natural fermented meju sample made in different regions and different fermentation stages in Liaoning province of China using Illumina MiSeq sequencing technology and metaproteomics technology.The results of this work will deeply understand traditional fermented meju microbial community characteristic and help to artificial inoculation at industrialized production and improve the quality of the soybean paste. |
