Study On Separation Of Haploids From Diploid Cells Of Saccharomyces Cerevisiae And Hybridization Breeding Of Strains With High Ethanol Production

On the basis of the work that we have got a group of high ethanol production diploid and haploid Saccharomyces cerevisiae strains, in order to improve the ethanol fermentation capacity and select higher ethanol production new strains than them, we screen elite strains for ethanol fermentation by spore separation and hybridization breeding. Diploid Saccharomyces cerevisiae strains ZJD3-3,ZJD3-4,ZJD3-7,ZJD3-9 and ZJD3 -11 (ZJD3series),haploid strains c36,c36,c36-9 and aneuploid strain C19 were used for investigating.Firstly, choose the optimum sporulation medium. After 7 days of growth on the McClary medium tubes at 25°C, reached a maximum sporulation rate of 47%. We got 71 haploid strains after sporulation of ZJD3 series. Testing their mating types and measuring the ethanol fermentation capacity, found that among all the mating types, the number of a type was far more than the number of a type. 4 high ethanol-production haploids were selected. The ethanol-production capacity of best strain zs-5 increased by 4.5% than its diploid parent strain, and 1 a mating type and 3 a mating type.Take the selected 4 strains and haploid strains c36,c36-8,c36-9 and aneuploid strain C19 as hybridization strains, and make group hybridization. We found that after 2h of crossing, hybrid cells arose, and cultured it on plate after 48h. A total of 124 hybrids were constructed by crossing and screen strains of better fermentation character by original selection and reselection. The result showed that more than 95% hybrids produced more ethanol than their parents strains .We got 6 strains finally, and they were named zj-1, zj-2, zj-3, zj-4, zj-5. zj-6.