Filamentous Saccharopolyspora erythraea bacteria are grown in medium containing glucose as the carbon source, ammonia as the nitrogen source, and sulphate as the sulphur source. No major products other than biomass are produced during cell growth. Sulphur is included easily in the stoichiometric equation if we use sulphuric acid (H₂SO₄) to represent the sulphur source and define the valence of S as +6. The molecular formula for S. erythraea biomass is found to be CH_1.73O₀.₅₂N₀.₁₇S₀.₀₀₃₂ and the biomass yield from glucose is 0.29 g g^-1.

(a) What are the oxygen requirements for this culture?

(b) If the medium contains 20 g l^-1 glucose and the culture proceeds until all the glucose is consumed, what minimum concentration of sulphate must also be included in the medium in units of gmol l^-1?