Study On Microbial Diversity In Fuzhuan Brick Tea

Fuzhuan Brick Tea is a kind of fully fermentation tea, which has the most complicated and unique process of production. On the surface of Fuzhuan brick Tea, there are thickly covered by kinds of bright yellow spots, which is commonly called "jinhua" by consumers and providers. This is important character that Fuzhuan Brick Tea different to the others. The abundance of "jinhua" is important factor of the quality of Fuzhuan Brick Tea. To make full use of microbial resources in Fuzhuan Brick Tea,improve quality of Fuzhuan Brick Tea,find the added value of its by-products,excavate the potential resources of Fuzhuan Brick Tea and develop the high additional value products with quickly fermentation,the microbial diversity was studied in this paper. Based on the different kind of Fuzhuan Brick Tea,the microbial divercity was studied by the technical analysis from PCR-DGGE and DNA sequencing.Meanwhile,by applying the technology of traditional microorganism cultures and DNA sequencing,we have obtain and reach the main Yeast in Fuzhuan Brick Tea,the results were as follows:(1) Firstly, applying the technology of traditional microorganism cultures and the examine by microscope,we have acquire the dispersive data. Then we found that Eurotium cristatum is the primary microorganism in Fuzhuan Brick Tea, it exists in the whole manufacturing process of Fuzhuan brick tea, also Eurotium repens and Eurotium rubrum, Aspergillus niger, Penicillium and so on. And Aspergillus niger and Penicillium is contaminative microorganism.By analyzing the value of water,we can get the relation between microorganism of Fuzhuan Brick Tea and the value of water.(2) According to the analysis of microorganism in Fuzhuan Brick Tea; using the liquid nitrogen grinding method and DNA extraction for different samples of Fuzhuan Brick Tea to obtain PCR amplification products; then through DGGE analysis to get the dominant microbial gene sequences of Fuzhuan Brick Tea. Determining DNA sequence in the database at the NCBI BLAST website (http://www.ncbi.nlm.nih.gov/BLAST/); Eventually determine the species of primary microorganisms of Fuzhuan Brick Tea. The results showed that:Eurotium cristatum exist in the whole manufacturing process of Fuzhuan brick tea, also Debaryomyces hansenii, Aspergillus niger, Eurotium repens,Eurotium rubrum,Penicillium and so on. Debaryomyces hansenii may have a special role in promoting the quality of Fuzhuan Brick Tea, but its specific mechanism remains to be studied.(3) Through the technology of traditional microorganism cultures and the examine by microscope,we obtain the dominant yeast in Fuzhuan Brick Tea.Then combining molecular DNA extraction and PCR gene amplification, determining DNA sequence in the database at the NCBI BLAST website (http://www.ncbi.nlm.nih.gov/BLAST/).Eventually determine the species of primary yeast of Fuzhuan Brick Tea. The results showed that:Debaryomyces hansenii is the primary yeast in Fuzhuan Brick Tea,which is firstly reported.This result has an important significance which will protect and enhance the special flavor of Fuzhuan Brick Tea,accelerate the fermentation of tea.(4) Study on the physiological characteristics of Debaryomyces hansenii,which is the primary yeast in Fuzhuan Brick Tea. We found thatthe optimum cultivation temperature of Debaryomyces hansenii is about 28℃;the optimum cultivation Nacl content with it is 8-10%, the optimum cultivation pH 4-7. Through fermentation mixed Debaryomyces hansenii and Eurotium cristatum,then extract the rough enzyme liquid.Based on the measurment of cellulose enzyme,we found that the fermentation mixed with two species of microorganism can increase cellulose transparent ring of diameter in the short growth,in virtue of Debaryomyces hansenii may improve the growth of Eurotium cristatum;While in the long growth, the cellulose transparent ring of diameter will decrease,for the reason that Eurotium cristatum may produce some material which can inhibit the growth of other microorganism.