Abstract

MONTES-RAMIREZ, Luz Mary; MEJIA-GUTIERREZ, Luis Fernando  and  CAICEDO-ERASO, Julio César. Electrical impedance spectroscopy, a tool for biotechnological applications with Lactobacillus casei ATCC 393. Rev. colomb. biotecnol [online]. 2021, vol.23, n.1, pp.55-61.  Epub Aug 11, 2021. ISSN 0123-3475.  https://doi.org/10.15446/rev.colomb.biote.v22n2.78171.

The application of electrical impedance spectroscopy (EIS) is a technique used to monitor, detect and quantify microorganisms of biotechnological interest, with the measurement of electrical parameters of rapid response of a medium inoculated at temperature and constant agitation by submerged electrodes. By making a comparison of the growth model and the plate count with the electrical response parameters, a correlation can be made to break the technological barrier between classical microbiology and rapid detection methods. The comparison of both techniques was performed to determine the maximum growth of Lactobacillus casei (L. casei) ATCC 393. It was found that after inoculation, after 24 h under microaerophilic conditions (37 °C), the maximum microbial growth was recorded by medium of the EIE, using the parameters |Z| (29,1057) and Deg-Deg0 (24,555°). In contrast to the plate count technique, maximum growth was estimated at 9 h. The experimental data obtained through the EIE were adjusted by a series RC circuit; later, the generated curves were adjusted to the growth models of Gompertz and Boltzman. Using the EIE technique, the impedance of the medium was the most efficient parameter for the estimation of the maximum exponential growth peak of L. casei. It was demonstrated that the EIE constitutes an alternative for the rapid detection of the microbial concentration in biomass production processes for the elaboration of probiotic food products.

Keywords : Electrical impedance spectroscopy (EIS); exponential growth; plate count; Lactobacillus casei.

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