Industrial Application of Fuzzy Control to Large-Scale Recombinant vitamin B_2 Production

摘要

A fuzzy control system featuring the identification of culture phases by fuzzy logic was applied to the large-scale recombinant vitamin B_2 (VB_2) production at the Fukuroi factory of Nippon Roche, fukuroi. Prior to actual operation, the knowledge base for fuzzy control was tuned and verified by a simulatiOn system. Only four rules, formuLated as IF approx THEN instructions and membership functions for state variables, are employed to control the feed rate and pH of the fed-batch culture. By applying fuzzy control, total VB_2 production and VB_2 yield was increased by 6-16% and 4-11% compared with conventional control, respectively. Operating stability was also improved. The large-scale fermentor used for VB_2 production has bee successfully operated under the control of the fuzzy system for more than 2 years.