arXiv subjects

P. Escalante-Minakata

Publications and source records attributed to P. Escalante-Minakata.

5 recordsLinked to original sources

arXiv2008

Application of multifractal wavelet analysis to spontaneous fermentation processes

An algorithm is presented here to get more detailed information, of mixed culture type, based exclusively on the biomass concentration data for fermentation processes. The analysis is performed with only the on-line measurements of the redox potential being available. It is a two-step procedure which includes an Artificial Neural Network (ANN) that relates the redox potential to the biomass concentrations in the first step. Next, a multifractal wavelet analysis is performed using the biomass estimates of the process. In this context, our results show that the redox potential is a valuable indicator of microorganism metabolic activity during the spontaneous fermentation. In this paper, the detailed design of the multifractal wavelet analysis is presented, as well as its direct experimental application at the laboratory level

physics.bio-ph↗

arXiv2008

An algorithm for real-time estimation of Mezcal fermentation parameters based on redox potential measurements

We present an algorithm for the continuous monitoring of the biomass and ethanol concentrations and moreover the kinetic rate in the Mezcal fermentation process. This algorithm performs its task having only available the on-line measurements of the redox potential. The procedure includes an artificial neural network (ANN) that relates the redox potential to the ethanol and biomass concentrations. Then a nonlinear-observer-based algorithm uses the biomass estimations to infer the kinetic rate of this fermentation process. The method shows that the redox potential is a valuable indicator of microorganism metabolic activity during the Mezcal fermentation. In addition, the estimated kinetic rate can be considered as a direct evidence of the presence of mixed culture growth in the process. In this work, the detailed design of the software-sensor is presented, as well as its experimental application at the laboratory level

q-bio.QM↗

arXiv2007

High-gain nonlinear observer for simple genetic regulation process

High-gain nonlinear observers occur in the nonlinear automatic control theory and are in standard usage in chemical engineering processes. We apply such a type of analysis in the context of a very simple one-gene regulation circuit. In general, an observer combines an analytical differential-equation-based model with partial measurement of the system in order to estimate the non-measured state variables. We use one of the simplest observers, that of Gauthier et al., which is a copy of the original system plus a correction term which is easy to calculate. For the illustration of this procedure, we employ a biological model, recently adapted from Goodwin's old book by De Jong, in which one plays with the dynamics of the concentrations of the messenger RNA coding for a given protein, the protein itself, and a single metabolite. Using the observer instead of the metabolite, it is possible to rebuild the non-measured concentrations of the mRNA and the protein

q-bio.QM↗

arXiv2007

Mixed-Cultures and Alcoholic Fermentations

The population dynamics of mixed-culture and sequential-cultures in fruit-must fermentation is a very interesting problem from both the theoretical and technological stand point. By mixed-culture we refer to those fermentations in which more that one strain/species are present from the beginning of the process; and by sequential to those in which different microorganisms are added along the process. These kinds of fermentations play a key role in industry of fermented beverages. The mathematical models of such processes should represent the dynamics of multiple species growing in a mixture of substrates as the fruit must composition includes an important proportion of hexoses and pentoses. Since the flavor is a basic aspect of beverages, and in general of all fermented foods, it is fundamental to study the population dynamics and its impact in the organoleptic properties, through the influence in the volatile compound profile. The goal of this paper is to present a panorama of the investigations of these fermentative ecosystems from a biological, mathematical, and technological stand point.

q-bio.PE↗

arXiv2007

Inferring mixed-culture growth from total biomass data in a wavelet approach

It is shown that the presence of mixed-culture growth in batch fermentation processes can be very accurately inferred from total biomass data by means of the wavelet analysis for singularity detection. This is accomplished by considering simple phenomenological models for the mixed growth and the more complicated case of mixed growth on a mixture of substrates. The main quantity provided by the wavelet analysis is the Holder exponent of the singularity that we determine for our illustrative examples. The numerical results point to the possibility that Holder exponents can be used to characterize the nature of the mixed-culture growth in batch fermentation processes with potential industrial applications. Moreover, the analysis of the same data affected by the common additive Gaussian noise still lead to the wavelet detection of the singularities although the Holder exponent is no longer a useful parameter

physics.bio-ph↗