Reference no: EM132735254

Two flasks of E. coli are grown in batch culture in the same medium (2% glucose supplemented with other macro- and micro-nutrients; no nitrate, no sulfate) and at the same temperature (37°C). Culture #1 is well aerated. Culture #2 is static and anoxic. After 16 hours the following observations are made: Culture #1 has a high cell density; the cells appear to be in stationary phase, and the glucose level in the medium is reduced to 1.2%. Culture #2 has a low cell density; the cells appear to be in logarithmic phase, although their doubling time is prolonged (over 1 hour). The glucose level is reduced to 0.2%.

Question: Why did culture #2 have so little glucose remaining relative to culture #1, even though culture #2 displayed slower growth and had less biomass?

And refer to the "electron tower", why a chemotrophic microorganism cannot use water as the electron donor and nitrate as the electron acceptor for energy conservation?