A microorganism is capable of utilizing glucose, methanol, and hexadecane as the carbon source. Its average cell composition (by weight) was analyzed to be 47% carbon, 6.5% hydrogen, 31% oxygen, 10% nitrogen, and the remainder ash. During cultivation, this microorganism converts the substrates O2 and ammonia into cells, carbon dioxide, and water. A batch culture was carried out to estimate the cell yield based on substrate and oxygen (kg cells/kg substrate or oxygen). Air was continuously supplied, and the exhaust gas was vented from the top of the bioreactor. A mass spectrometer was available for gas composition analysis. The water vapor was removed from both inlet and outlet gases before analysis. The inlet gas was composed of 21% oxygen and 79% nitrogen. The composition of the gas at the exit (on a volumetric basis) is listed in the table below:

a) Write down the stoichiometric reaction equation for each substrate.

b) What are the estimated cell yields, based on the substrates and oxygen, for each of the three substrates? What are the RQs? (RQ is respiratory quotient = mole carbon dioxide produced/mole of oxygen consumed.)

c) For a bacterium with 8% of its dry mass as nitrogen, what is the yield coefficient for NH3?