Effect of Different Growth Media on Algae’s Ability for Carbon Dioxide Biofixation

Carbon dioxide makes up 72% of all greenhouse gases produced, which makes it the leading source of air pollution. Certain green algal species such as Chlorella vulgaris fix the carbon dioxide into fatty acids present in cells in a process known as “carbon dioxide biofixation”. This project tests the effect of different algal growth media on the efficiency of Chlorella vulgaris’s carbon dioxide biofixation. In the testing process, we added Chlorella vulgaris to four bottles, each containing four different substances (distilled water, Blue Green 11 medium, Bold’s Basal Medium, and Guillard’s f/2 medium), and cultured for eight days. Each algae and medium mixture was then divided equally into three smaller bottles and rotated for three days. To compare data, we measured the change in carbon dioxide content by subtracting the carbon dioxide content of the bottles with algae to a similar bottle without algae. The results for the average change in carbon dioxide content were 59.3 ppm for Blue Green 11 medium and algae, 50.6 ppm for Guillard’s medium and algae, 22.6 ppm for Bold’s Basal Medium and algae, and 10 ppm for distilled water and algae. The Blue Green 11 medium most effectively decreased carbon dioxide content of the bottles. This supported our hypothesis that algae's capacity for biofixation can be greatly enhanced through the effective use of media, a finding that has extensive real-world benefits in reducing pollution.