A fuzzy control system was organized and applied to the control of ethanol concentration in a fedbatch cultivation process for emulsan production by Acinetobacter calcoaceticus RAG-1. The membership functions and fuzzy rules were determined by sets of data and experiences obtained from the preliminary culture experiments. The input variables, error (the difference between the set point value and the process variable) and the change of the error, were fuzzified by using the membership functions and the output variable, change of the ethanol feed rate, was inferred based on the membership functions and the given fuzzy rules. To obtain the numerical value for the output variable, the center-of-gravity method was used in the defuzzification procedure. The results showed that the ethanol concentration was well regulated around optimal level and the emulsan yield was increased compared with that of the cultivation controlled by the conventional feedback control loop.

Fuzzy Control Fed-batch Cultivation Emulsan Acinetobacter calcoaceticus RAG-1

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