Abstract:One strain, named as Bacillus sp. F2, of which flocculent ability can reach 84%, was separated. Flocculent genomic library was constructed.A strain of Bacillus coli. Positive clone FC2, which could express flocculent activity, was acquired after selection. Infrared spectrum analysis demonstrated that FC2’s flocculent characteristic inherited from the original flocculent bacterium F2. The cloning bacterium were divided into FLO1 phenotypes on the basis of their response to sugar inhibition. Related physiological and biochemical characteristics of the strains were studied. The results show that the flocculation of FLO1 phenotype is only inhibited by mannose. It is sensitive to Ca2+ and pH, tolerant to temperature and storage period.