Identification And Analysis Of Microbial Community Structure For Gujing Liquor Daqu

In the traditional brewing process, Daqu determines the brewing quality to agreat extent. Different types of Daqu contain different microbial biodiversities. Thisstudy identified the microbial community composition of GuJing liquor Daqu basedon16S rDNA sequence analysis method. Meanwhile, the preliminary study of rapidquantification technology for Daqu species provided the necessary reference forfurther development of practical rapid quantitative techniques.This research is mainly composed of four parts:First, PCR amplification conditions were explored. Second, by using thetechnology of TA cloning and blue-white colony screening,16S rDNA clones werecollected, stored, replicated and sequenced. Third, all effectively sequenced cloneswere subject to Blast analysis to identify microbial species. Phylogenetic trees wereconstructed to display relationship among Daqu species. Fourth, several strategies torapidly quantify the main Daqu species were proposed, designed, and partiallyconfirmed by experiments.Conclusions obtained in this research are as follows:(1) GuJing Daqu microbial community was firstly characterized and analysed atthe molecular level. It is mainly composed of Firmicutes and Proteobacteria. Thereare six main dominant species, namely Virgibacillus, Bacillus, Lactobacillaceae,Pantoea, Staphylococcus and Thermoactinomycetaceae(2) By comparing microbe community structure of medium temperature Daqu.and high temperature Daqu, the former has a larger diversity.(3) By constructing phylogenetic tree, one potential new Bacillus species strainis found, namely strain of GJ-1-20in the medium temperature Daqu.(4) Through the initial study of rapid quantitative technology, we found that it isvery difficult to distinguish20or more species rapidily and quantitativly only on thebasis of these very similar16S rDNA sequences (around1500bp), even forTaqMan-MGB probe technology. Because most GuJing Daqu microbe genomes arenot expected to complete within the next ten years, the development of low-costsingle-base-resolution quantification technology only based on limited16S rDNAsequences is very worth waiting.