Effects of Bacteria, Light, and Moisture on Biodegradation

The purpose of this experiment was to find the optimal conditions for the greatest percentage of biodegradation of plastic to occur. Using the statistical design of experiment method (DOE), the type of bacteria, amount of moisture, and exposure to light were varied. About one gram of biodegradable plastic was buried in 100 mL of soil in small clay pots. The appropriate bacteria was cultured, transferred to nutrient broth solution, then poured into the appropriate pots. The appropriate amount of water was also added, and the appropriate pots were either covered with tin foil to prevent light or covered with clear saran wrap. Three standards were also run to ensure accurate results. After four weeks, the samples were dug up, massed, and analyzed. The amount of water had the greatest single factor effect, while the type of bacteria and the exposure to light had the greatest two factor effect.

Research Done By:

Stephanie Potter
Sterling Heights High School

Jane Sturgell
Eisenhower High School