[Cloning of flocculent gene and expression in industrial yeast strain]

The partial genomic library of Saccharomyce cerevisiae FL189 possessing strong flocculation ability was constructed using Yeast-E. coli shuttle plasmid YCp50 as vector. Recombinant plasmid containing flocculation gene was obtained by screening the growth of transformants on the selective medium and measurement flocculation, designated as pCF1.pCF1 was introduced into industrial yeast strain PJ208-5-15. Six transformants PJ208-5-15-1(pCF1)-PJ208-5-15-6(pCF1) possessing strong flocculation ability were obtained. The results of Southern blot and restriction endonuclease analysis showed that the insert is about 4.3 kb and could hybridize with the probe (2.6 kb Eco RV fragment of FLO1). Flocculation ability assay indicated that the transformants possess strong flocculation ability. Hence, the gene controlling flocculation phenotype exists in the cloned DNA fragment. The restriction endonuclease analysis and the sequence analysis of the insert DNA fragment are in progress.