About AE   About NHM   Contact Us   Terms of Use   Copyright Info   Privacy Policy   Advertising Policies   Site Map
Custom Search of AE Site
spacer spacer


Lana Hays


dry lima beans
Palmolive detergent
distilled water
centrifuge tube
fresh papaya juice
graduated cylinder (10ml)
non-iodized salt
granulated sugar
epsom salts
15 ml test tube
Bufferin (325mg)
test tube rack or 250 ml beaker
ice cold 95% ethanol
glass stirring rod


Lima Bean Bacteria Suspension:
Place 1-2 handfuls of dry lima beans in a large jar and fill halfway to the top with distilled water. Cover and sit in a warm room for 2-3 days. Culturing longer than three days often results in more DNA but it usually shears. Pour through a strainer and keep the liquid for the extractions.

Prep buffer solution:
57 g granulated sugar
3 g epsom salts
1 buffered aspirin
add distilled water for a total volume of 500 ml

50% detergent solution:
20 ml detergent
20 ml distilled water

Salt solution:
29.2 g non-iodized salt
add distilled water for a total volume of 250 ml


  1. Add 14 ml of the bacterial suspension to a centrifuge tube and spin in a balanced centrifuge for 5 minutes.
  2. Pour off the liquid (supernatant) and discard. You want to keep the pellet as this has your cells.
  3. Add 5 ml of prep buffer and resuspend your cells with a pipet.
  4. Add 1 ml 50% detergent solution.
  5. Add 1 ml papaya juice.
  6. Add 2 ml salt solution and shake for 2 minutes.
  7. Place the tube in the centrifuge and spin for 5 minutes. Make sure the centrifuge is balanced.
  8. Draw off 7 ml of the supernatant (liquid) as this has the DNA and place it in a clean test tube.
  9. Pour 7 ml of ice cold ethanol carefully down the side of the tube.
  10. Let the mixture sit undisturbed 2-3 minutes until the bubbling stops.
  11. The DNA will float in the alcohol. Swirl a glass rod at the interface of the two layers. You may see some tiny threads of DNA but are more likely to see fluffy, white sheared DNA.
Modified from: "Generic, All Purpose DNA Extraction from Meat Protocol" Judy Brown "Mammalian DNA Extraction" Theresa Knapp

Onion | Wheat Germ | Lima Bean Bacteria | Thymus | Yeast | Data Sheet and Questions | Design Your Own DNA Extraction Protocol | Teacher Information | References

Activities-To-Go Index

Activities Exchange Index

Custom Search on the AE Site