4 sheep blood agar plates inoculated with a culture of bacteria (Staphylococcus epidermis) were used in this experiment. Each of these plates were then placed in a Mylar resealable bag and filled with a different gas. The gases used in this experiment were carbon dioxide (CO2), nitrous oxide (N2O),oxygen (O2), and ordinary air (control group). These bags were then placed in an incubator for 24 hours.I performed three trials.
On an average, the plate placed in the bag with oxygen had the most number of bacterial colonies, while the plate in the carbon dioxide bag had the least number. The colonies in O2 plate were bigger in size(about 2X the CO2). However, the colonies in N2O were bigger than those in O2(about 2.5X the CO2)even though their number were less.
My conclusion is that various gases do indeed have an influence on the growth of aerobic bacteria and aerobic bacteria grow the best under oxygen. However the disparity in size between 02 and N2O needs to be further studied.
This experiment is about the influence of various gases on the growth of aerobic bacteria.
Science Fair Project done By Anirudh G. Madabhushi