Team:Penn/CdTolerance

In order to appropriately determine the effectiveness of using AMB-1 as a viable bioremediation alternative to E.Coli, we performed tests to measure the natural tolerance of both strands to the pollutant cadmium. The experiment allowed us to identify the threshold concentration of normal growth of bacteria. We used the tests to ensure that the AMB-1 strain could withstand the levels of cadmium present in the environment currently.

We were able to measure the growth curves of three different strains of bacteria: NEB Turbo, MG1665 and W3110. The growth curve of W3110 is shown here. To see how the other two strains of bacteria react under cadmium challenge, visit the supplementary information.

From the data, we can conclude that Magnetospirillum magneticum AMB-1 maintains normal growth under 10 uM concentration of cadmium and showed no growth in media with above 100 uM of cadmium ions. E.Coli showed unaffected growth in media with less than 500uM of cadmium ions and showed zero growth with 5000uM of cadmium ions. Although E. coli seemed to be inherently more tolerant towards cadmium than AMB-1, the data does show that AMB-1 can tolerate cadmium concentrations usually toxic to ecosystems. This shows that the strain could potentially still be a viable bioremediation tool.

We recommend future studies into the effect of cadmium on these strains of bacteria under different growth media and determination of the threshold concentration for normal growth.