(a) The maximum theoretical yield of ethanol from glucose is 2 mol ethanol/mol glucose.

(b) If ethanol is the sole extracellular product of energy-yielding metabolism, the maintenance coefficient is 0.16 kg/kg/h, and the maximum specific growth rate is 0.5 h-1, the observed product yield from substrate will be 0.12 kg ethanol/kg substrate. The observed biomass yield from substrate will be 3.5 kg/kg.

(c) The efficiency of ethanol production is 0.12/2, or 0.06.

(d) The specific rate of ethanol production is 0.06 mol ethanol/mol glucose/h. The proportion of growth-associated ethanol production is 0.12/3.5, or 0.03. The proportion of non-growth-associated ethanol production is 0.06-0.03, or 0.03.

Explanation:

(a) The maximum theoretical yield of ethanol from glucose is 2 mol ethanol/mol glucose. This is because the stoichiometry of the reaction dictates that for every mole of glucose that is fermented, 2 moles of ethanol and 2 moles of carbon dioxide are produced.

(b) If ethanol is the sole extracellular product of energy-yielding metabolism, the maintenance coefficient is 0.16 kg/kg/h, and the maximum specific growth rate is 0.5 h-1, the observed product yield from substrate will be 0.12 kg ethanol/kg substrate. The observed biomass yield from substrate will be 3.5 kg/kg. This is because the maintenance coefficient represents the amount of substrate that must be consumed in order to maintain the cells, and the maximum specific growth rate is the rate at which the cells can grow.

(c) The efficiency of ethanol production is 0.12/2, or 0.06. This is because the observed product yield from substrate is divided by the maximum theoretical product yield in order to calculate the efficiency.

(d) The specific rate of ethanol production is 0.06 mol ethanol/mol glucose/h. The proportion of growth-associated ethanol production is 0.12/3.5, or 0.03. The proportion of non-growth-associated ethanol production is 0.06-0.03, or 0.03. This is because the specific rate of ethanol production is the amount of ethanol that is produced per unit of time, and the proportion of growth-associated ethanol production is the amount of ethanol that is produced as a result of cell growth.