You want a quick start by adding sufficient seed but must avoid the cost of using too much. More sugar results in more growth but prolongs the growth phase. Since product formation commences only after the growth phase is over, there must be a compromise between getting abundant growth and having sufficient time for the organisms to make product. Scheduling restraints for the plant fix the total time for a run. Oil is nutritious and can substitute for sugar, except that excess oil is harmful both to growth and to product formation.
Oil also serves as an antifoam agent.
High air flows promote foaming and greatly increase oil consumption. This relatively inexpensive complex nitrogenous material from soybeans contains some vitamins, other undefined essential ingredients, and toxic ingredients. This complex nitrogenous material, a byproduct of making alcohol from corn grain, contains some of the same factors as soymeal. The same comments apply. Oxygen is essential for both the growth and production phases.