Problem
I. Given a natural lake environment with 100 species of bacteria, why does the species with the fastest generation time not overwhelm the others? Or does it?
II. Escherichia coli is a facultative species, able to grow with or without oxygen. What would it take to make this organism a strict anaerobe?
III. Two spore formers-Geobacillus thermophilus and Bacillus coagulans-have D-values at 121 oC of 5 minutes and 0.07 minutes, respectively. How could the spores from these organisms have such different D-values? Hint: Find the organisms' optimal growth temperatures.
IV. Phage therapy is touted by some as a solution to antibiotic resistance. Discuss three possible problems we could encounter with phage therapy and how we could overcome them.
V. With respect to bacteria, is the physiological effect of hydrochloric acid (HCl) at pH 4 the same as that of an organic acid at pH 4?