Sunday, August 8, 2010

Making your own Petri Dish Medium by Joseph Parish

No one would argue the point with you that the commercial microbial media would produce the ideal growth environment for micropropagation techniques. These commercially purchased medium dishes provide the proper nutrients for optimum growth and sustainability needed for generation of tissue cultures. The major problem encountered here for the home laboratory is the high cost associated with these commercial units.

Since necessity is considered the mother of inventions we can actually create our own homemade gelatin plates for growing tissue cultures in at a fraction of the cost we would spend for the commercial dishes. The homemade medium formula that I am about to discuss can be poured into your selection of sterile Petri dishes as you require. This is a general formula and you should feel free to add your own selection of nutrients as necessary.

As an added bonus in the event that you find the commercial Petri dishes themselves to be a tad expensive, we can also resolve that problem for you. It is a simple matter to substitute foul muffin cup liners for Petri dishes. I have in the past even employed sterilized baby food jars as dishes with a degree of success.

Materials needed for the Medium

  • 4 crushed beef bouillon cubes
  • 4 cups of distilled water
  • Foil muffin cups liners
  • Muffin pans
  • Measuring spoons
  • 4 envelopes of Plain unflavored gelatin
  • 8 teaspoons of Sugar
  • A selection of Ziploc bags

To begin this formula take a medium size sauce pan and mix the 4 envelopes of plain unflavored gelatin together with four cups of distilled water. Add to this 8 teaspoons of sugar and 4 finely crushed bouillon cubes. Slowly bring the mixture to a boil being sure to stirring constantly.

Prepare the foil muffin liners by placing them into the muffin pan. Allow the mixture to cool slightly and then fill the foil muffin cup liners 1/3 to ½ full with the hot gelatin solution. If you are using commercial Petri dishes fill them in a similar manner.

Allow the gelatin to cool to a solid at this time. Refrigerate if you so desire. After the gelatin has become a solid remove the foil muffin liners from the pans. These liners can be placed into a Ziploc bag and refrigerated until needed. Remember at this point they are sterile and you should not touch the surface with your hands.

Use the medium up with 2 to 3 days after making it. The above formula will make anywhere from 25 up to 30 dishes.

Copyright @2010 Joseph Parish