Question

Assume that the original growth curve was done using well-aerated medium (lots of oxygen). Predict what the growth curve would look like if the E. coli culture was grown under anerobic conditions. How would B. subtilis grown under the same conditions compare?

Answer 1

E. coli in the presence of oxygen undergo aerobic respiration but in the absence of oxygen energy is generated by coupling membrane associated electron transfer reaction using an electron acceptor other than O_2. These electron acceptor have lower reduction potential than oxygen. As a result respiration is less efficient and slower than aerobic respiration. The E coli growth curve under both aerobic and anaerobic condition is shown in the image below-

B. subtlis is a strict aerobes, meaning they can grow only in the presence of oxygen and cannot undergo fermentation. So the growth curve would be look like given below-