“…At the beginning of cultivation, if r glc,R < r glc,M , then r glc = r glc,R and the regulator becomes a positive feedback loop, to imitate an accelerating establishment of the enzyme pool for glycolysis. A negative feedback of m is introduced in the regulator model because the enzyme pool may be diluted by the cell growth [36]. If r glc,R > r glc,M , then r glc = r glc,M and the regulator will work in a servo mode to follow up r glc,M .…”