Product Code TM 172

  • Description

    Morris and Eddy described this complex medium for the isolation and enumeration of wild yeasts in pitching yeast in the brewery industry. Walters and Thiselton used a liquid synthetic medium containing lysine as sole nitrogen source and found that many types of yeast utilize lysine. Later Morris and Eddy also formulated solid lysine medium. Most of the Saccharomyces strains employed in the brewery industry and other fermentative industries do not use lysine, whereas the wild strains do.
    Lysine Medium exploits this differential behavior to separate both types of yeasts. Morris and Eddy recommended surface inoculation of washed aliquots from the yeast mass; 0.2 ml suspension of 107 cells/ml is the best. Sample is incubated at 25?C and examined daily, enumerating all the colonies that have grown (lysine positive). The degree of contamination is expressed as the number of wild yeast cells per million cells of the original inoculum. The number of cells in the inoculum is important as small number of cells about 100 to 1000 grow to a limited extent while 10,000 brewing yeast cells provide a direct measure of contaminant wild yeasts.

  • Principle

    for isolation and enumeration of wild yeasts in pitching yeasts

  • Microorganism

    • Pichia fermentans
  • Industry

    • Food & Beverages
  • Pack Size

    • 100 gm
    • 500 gm
  • Downloads

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