Abstract: Genome DNA was respectively extracted from fermented beer liquid, beer yeast (S.cerevisiae), yeast(K), beer- contaminating bacteria(T), E.coli.DH5α and Bacillus YK-1R by various methods to produce different cell-disruption efficacy.Glass bead-beating method has the yeast cells lysis efficacy beyond 90%. Although the lysozyme or freeze-thaw method shows that bacteria lysis efficacy can reach 99%～100%, yet can only reach 15%～28% for yeast cells lysis efficacy. However the use of phCH2Cl has lysis efficacy for both bacterial and yeast cells reaching 100%. The genome DNA extracted by either glass beads, or lysozyme or phCH2Cl reaches beyond 23kb in DNA size and good integrity when assayed in gel electrophoresis. The genome DNA extracted through phCH2Cl is the most clear and sharp figure, DNA yield can achieve 108μg/g of wet-organism and the RAPD- PCR is reproducible. This protocol has potential for detection of beer-spoilage microorganisms.

Key words: ferment liquid of beer, DNA extraction, PCR amplification