Why does E-coli grow in nutrient broth better than in thio-glycolate broth?
The purpose of the thio-glycolate broth, which, if memory serves, is a semi-solid agar, is to determine oxygen requirements. E. coli is a facultative anaerobe which means it prefers aerobic conditions but can grow (to a lesser extent) anaerobically. So you will see growth at the top of the thio-glycolate tube mainly where there is oxygen, perhaps some just along the shallow stab line from inoculation. It will not permeate throughout the medium since it prefers aerobic respiration and oxygen is available at the top.
