This paper presents a methodology to detect on line the physiological state of strains in bioreactor. The biologic reactions means that one of the pathways of the metabolism is activated and in this case the microorganisms will produce or will consummate The discrete-event system (DES) is synthesised applying the Maximum of Modulus of the Wavelet Transform on measured signals constrained to the biotechnologist expert validation. The determination of Holder Coefficient by Differential Evolutionary Algorithms allows to make the difference between different discontinuities and to obtain the segmentation of the signals. All these evaluations leads to associate the signals variations during the time to physiological states.