Analysis of impedance spectrum of electroporated biological cell suspensions allows evaluating the state of permeabilization produced by the applied electric field. In this article we used a genetic algorithm to determine parameters of a proposed model for the impedance of suspension adjusting them numerically in order to minimize the error in relation to experimental spectra of Kluyveromyces marxianus CBS 6556 yeasts suspended in distilled water. It was possible to determine the variation of conductivity of suspension avoiding the influence of electrode polarization and dielectric dispersion due to interfacial and diffusion polarization on the cell surface. It was observed that the conductivity in the range of 1 to 100 KHz increases 2.5 times with pulses of 400 KV/m.