Abstract: The mechanism of interaction between Ketogulonicigenium vulgare and Bacillus megaterium was investigated for 2-keto-L-gulonic acid (2-KGA) mixed culture. Based on the metabolic pathway analysis in K. vulgare, a macrokinetic model was constructed, where, a first-order closedloop regulator model was introduced to describe the induction of the enzyme pool responsible for the growth of K. vulgare at the beginning of the cultivation. The model describes the balance of intracellular substance and energy flow rates. The key reaction rates such as the specific substrate consumption rate, the specific growth rate, the specific acetyl-CoA formation rate as well as the specific oxygen uptake rate are obtained with this model. The specific substrate consumption rate and the specific growth rate are then coupled into a bioreactor model such that the relationship between substrate feeding rate and state variables is set up. The experimental validation results were presented.  

Key words: Ketogulonicigenium vulgare, Bacillus megaterium, 2-keto-L-gulonic acid mixed culture, structure model, metabolic pathway