The Fermentation Characteristics Of Saccharomyces Cerevisiae St-01 And Scar Marker

Saccharomyces cerevisiae is the material of this study. Firstly, we had finished the beer fermentation, then selecting a strain of ST-01 by detecting some parameters of fermentation. Secondly, we selected the RAPD(random amplified polymorphic DNA) markers and translated these markers to SCAR(sequenced characterized amplified region) markers. This molecular marker method overcomes the disadvantage of RAPD marker and holds its advantages which are random and fast. It has provided the accurate data for the exploration the fast and accurate molecular markers on brewing yeast, simultaneously also protected its patent strain for the production enterprise and provided a quickly and accurate method.This research chose the yeasts which are good fermentation performance. These 8 brewing yeasts can be used in the beer fermentation. We collect and analyse the fermentative parameters. Each parameter of fermentation is consistent during the same experiment. The result indicated: ST-01 has good performance in yeast flocculation and CO2 production. It is up to the peak value of diacetyl which is 0.55 mg/L on the 8th day, It can be deoxidized subsequently. At the last, the content of diacetyl is reduced to 0.05 mg/L. It means the beer is mature rapidly. The alcohol content is up to 4.536 g/100ml and the fermentation degree is 64.74% in the last period of fermentation. Other 7 yeasts are worse performance than ST-01 with detecting some fermentation parameter. So ST-01 is a good brewing yeasts for beer fermentation.We have founded the DNA characteristic sequence of ST-01 to other 22 yeasts for taking the molecular marker. We extracted the DNA of 23 yeasts which are preserved by our laboratory. Then we amplified these DNA with random primers. The RAPD system is: yeast DNA 120 ng, 2.5mM Mg²⁺, Taq 1U, 200μM dNTPs, 10pmol random primers, the all volume is 25μL. PCR process is : 93℃2 min, 36℃1 min, 72℃2 min one cycle;93℃1 min, 36℃1 min, 72℃2 min, 40 cycles;93℃1 min, 36℃1 min, 72℃10 min one cycle. 50 random primers were tested to RAPD analysis. 2 effective primers named P09, P46 were selected, 4 strains(2.412,ST-01,SK-26,ZD-01) could amplify 433bp fragment with P09, and 3 strains(2.1882,ST-01,NJ-02) could amplify 665bp fragment with P46. These two DNA fragments were cloned in pUCmT plasmid and amplified in E.Coli DH-5α. Selected the correct clones. Then extracted the plasmid DNA and sequenced it after double digestion. Designed the SCAR primers with software. The RAPD markers of ST-01 could be translated into SCAR markers. Only the ST-01 has the two DNA fragments simultaneity. ST-01 is also different from other 22 yeasts on DNA sequence.In this paper, we make the SCAR-Sc433 and SCAR-Sc665 to be the SCAR markers could afford some new idea for finding out the difference of Saccharomyces cerevisiae strains, markering and breeding the industrial strains.