Media Preparation
PDYA: POTATO DEXTROSE YEAST EXTRACT AGAR
To Make 1 Liter:
250 grams potatoes; Do not peel. Scrub clean, cutting out eyes and bad spots
20 grams Agar. Cut into 1/2" pieces.
10 grams Dextrose, Anhydrous
1.5 grams Yeast Extract
Rinse and drain cut potatoes twice with tap water and once with distilled water. Add 1 liter distilled water to the potatoes. Cook until potatoes are tender. Filter the potato broth through two layers of cheese cloth. Save the broth and discard potatoes. Add distilled water to broth bringing volume up to 1 liter. Heat the 1 liter of broth to a boil. While stirring slowly add agar, dextrose and yeast extract. Stir until dissolved, watch carefully or it will boil over.
Autoclave for 15 minutes at 121C.
Place Potatoes into large pyrex flask
Potatoes are rinsed twice with tap water, and a third time with distilled water.
Prepare Agar
In a second flask, place 20 grams of Agar and one liter of distilled water. Place potato and Agar OPEN flasks in a metal pan.
Melt Agar and Cook Potatoes
Place the OPEN flasks (on a metal pan) in an autoclave. Autoclave on 'steam bypass' for 45 minutes. (Steam bypass - 100 C at 8 pounds pressure)
Measure ingredients
While potatoes and Agar are cooking, weigh out 10 grams of Dextrose and 1.5 grams of Yeast Extract.
Cool Potatoes and Agar
Set up a 1 liter plastic cylinder with glass funnel lined with 2 layers of cheesecloth while potato broth is cooling.
Filter the Potato broth
Filter the potato broth by pouring through the cheesecloth into the cylinder. Add distilled water if needed, to bring the volume in the cylinder to 1 liter. Add Dextrose and Yeast Extract to the melted Agar and swirl to mix. Mix filtered potato broth and Agar by pouring back and forth between the flask and the cylinder four times.
Pipet at once into Test tubes
If making test tubes, pipet at once using a pipeter. Make sure to flush pipeter with hot water when done.
