Enrichment Protocol for Saccharomyces cerevisiae:

Golden delicious apple chunks

Plate on YPD solid media (per liter of water):

• 10g yeast extract
• 20g peptone
• 200g dextrose
• 20g agar
• 1 pellet NaOH

This media was the definitive step in the isolation of S. cerevisiae.  Basic requirements for optimal yeast growth were achieved through the use of peptone, yeast extract, and NaOH.  The agar solidified the liquid media.  The most important ingredient for enrichment of solely S. cerevisiae was the high dextrose content.  This excluded the growth of competing bacteria and molds.

Store at 30⁰C for 96 hours

Confluent growth

Isolate individual colonies by streak plate to view colony morphology

Double check identity of organism by microscopic observation:

• evidence of budding on wet mount
• evidence of inclusion bodies with iodine stain
• evidence of ascopore formation by staining with malachite green