The Characteristics of Mixed Culture Where One Type of Microorganism Assimilates the Metabolite Produced by Another

摘要

Unstructure models were developed for a mixed culture where one microorganism assimilates the metabolite produced by another microorganism. The model system was a mixed culture using Lactobacillus delbrueckii and Ralstonia eutropha where the former assimilates glucose and produces lactic acid, and the latter assimilates lactate and produce poly #beta#-hydroxy butyrate (PHB). Performance improvement is shown for the mixed culture over a single culture for chemostat using the model developed. Since the optimal dissolved oxygen (DO) concentration is different for each microorganism, we developed another model which takes into account NH_3 concentration on the cell growth and PHB production by R. eutropha. Then the optimal time-profile for NH_3 concentration is derived using the Maximum principle. It is found that high PHB production could be attained even if NH_3 concentration is not controlled if initial NH_3 concentration is appropriately selected.