E. coli Bacterial Growth Study

Extract

[...] Bacterial growth follow-up of E. coli by measuring the optical density To study the growth, we studied the evolution of the optical density (D. by taking 1 mL (except at T0 and T120 where 3 mL must be taken) of a culture of E.coli every 20 minutes for 2 hours at 37 degrees. During the 2-hour experiment, we can observe that our culture of E.coli in our erlenmeyer at 37 degrees becomes turbid, it is therefore interesting to measure the optical density during the experiment. [...]

[...] Conclusion : We have, during this lab, studied the bacterial growth of the bacterium E. coli. By measuring the optical density, we found that this bacterium takes approximately 30 minutes to reproduce by scissiparity (generation time). However, upon searching in the literature, we note that this bacterium has a generation time of 20 minutes. This difference is certainly due to the fact that some of our values are incorrect. In fact, we observe, thanks to our calibration range, that some DO values of the culture of E. [...]

[...] The objective of this lab is to determine the generation time G (i.e. the time it takes for the bacterium to reproduce by scissiparity) as well as its specific growth ? (this represents the increase of all the components of an organism). The bacteria (E. coli here) reproduce by scissiparity: each cell will grow and divide into two daughter cells that will grow and divide into two daughter cells each. The generation time G and specific growth ? will be determined by measuring the optical density (using a spectrophotometer). [...]

[...] Thus, ? is equal to a : ? = 0.0222 min-1 Let's calculate the generation time G = Ln2/? = 31 minutes According to our results, E. coli met 31 minutes to achieve its generation time (that is to say its reproduction by scissiparity as stated in the introduction). II) Growth monitoring by counting on Petri dishes: The purpose of this experiment is to determine the number of bacteria E. coli, before and after two hours of culture at 37 degrees. [...]

[...] coli by counting on a Petri dish. This count shows us that the reproduction of this bacterium is extremely rapid, it can produce billions of new individuals in the space of 2 hours. Thus, the generation time of E. coli is extremely low, unlike other bacteria such as L.acidophilus = 100 minutes) or M.tuberculosis = 3 days). Our bacterium E. coli it reproduces very quickly, which makes it the subject of choice for study in the laboratory. Bibliography : http://umr5558-shiny.univ-lyon1.fr/web/modélisation-de-la-croissance-des-micro-organismes.html#:~:text=Mesure%20de%20la%20 bacterial growth&text=or%20by%20a%20measure%20of%20 20de,with the number of bacteria. [...]