Evaluation of wavelength selection methods for 2D fluorescence spectra applied to bioprocesses characterization

Masiero, Sara Scomazzon; Trierweiler, Jorge Otávio; Farenzena, Marcelo; Aragão, Marcelo Escobar; Trierweiler, Jorge O.; Ranzan, Cassiano

doi:10.1590/s0104-66322013000200007

Cited by 6 publications

(2 citation statements)

References 26 publications

(36 reference statements)

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“…On-line control of the fermentation process usually involves determination of pH and temperature. However, other key parameters of the fermentation process such as concentrations of metabolite, substrate, and cellular density need further investigation [4]. The key fermentation process parameters are not usually examined due to the expensive and time-consuming measurement methods [5].…”

Section: Introductionmentioning

confidence: 99%

Application of Two-Dimensional Fluorescence Spectroscopy for the On-Line Monitoring of Teff-Based Substrate Fermentation Inoculated with Certain Probiotic Bacteria

Alemneh

Emire

Jekle

et al. 2022

Foods

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There is increasing demand for cereal-based probiotic fermented beverages as an alternative to dairy-based products due to their limitations. However, analyzing and monitoring the fermentation process is usually time consuming, costly, and labor intensive. This research therefore aims to apply two-dimensional (2D)-fluorescence spectroscopy coupled with partial least-squares regression (PLSR) and artificial neural networks (ANN) for the on-line quantitative analysis of cell growth and concentrations of lactic acid and glucose during the fermentation of a teff-based substrate. This substrate was inoculated with mixed strains of Lactiplantibacillus plantarum A6 (LPA6) and Lacticaseibacillus rhamnosus GG (LCGG). The fermentation was performed under two different conditions: condition 1 (7 g/100 mL substrate inoculated with 6 log cfu/mL) and condition 2 (4 g/100 mL substrate inoculated with 6 log cfu/mL). For the prediction of LPA6 and LCGG cell growth, the relative root mean square error of prediction (pRMSEP) was measured between 2.5 and 4.5%. The highest pRMSEP (4.5%) was observed for the prediction of LPA6 cell growth under condition 2 using ANN, but the lowest pRMSEP (2.5%) was observed for the prediction of LCGG cell growth under condition 1 with ANN. A slightly more accurate prediction was found with ANN under condition 1. However, under condition 2, a superior prediction was observed with PLSR as compared to ANN. Moreover, for the prediction of lactic acid concentration, the observed values of pRMSEP were 7.6 and 7.7% using PLSR and ANN, respectively. The highest error rates of 13 and 14% were observed for the prediction of glucose concentration using PLSR and ANN, respectively. Most of the predicted values had a coefficient of determination (R2) of more than 0.85. In conclusion, a 2D-fluorescence spectroscopy combined with PLSR and ANN can be used to accurately monitor LPA6 and LCGG cell counts and lactic acid concentration in the fermentation process of a teff-based substrate. The prediction of glucose concentration, however, showed a rather high error rate.

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Section: Introductionmentioning

confidence: 99%

Application of Two-Dimensional Fluorescence Spectroscopy for the On-Line Monitoring of Teff-Based Substrate Fermentation Inoculated with Certain Probiotic Bacteria

Alemneh

Emire

Jekle

et al. 2022

Foods

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“…The more recent development of multi-wavelength fluorescence spectroscopy in combination with sophisticated data analytical methods has allowed simultaneous monitoring of several fluorophores. The technique has among others been applied for monitoring cultivations of bacteria, 5–7 filamentous fungi, 8,9 yeast 10,11 and mammalian cells. 12,13 In such cultivation processes pH is normally controlled and kept constant at a set-point value.…”

Section: Introductionmentioning

confidence: 99%

Weighted PARAFAC and Nonlinear Regression for Handling Intensity Changes in Fluorescence Spectroscopy Caused by pH Fluctuations

2016

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Fluorescence spectroscopy is a sensitive and selective technique, which can be of great value in bioprocesses to provide online, real-time measures of chemical compounds. Although fluorescence spectroscopy is a widely studied method, not much attention has been given to issues concerning intensity variations in the fluorescence landscapes due to pH fluctuations. This study elucidates how pH fluctuations cause intensity changes in fluorescence measurements and thereby decreases the quality of the subsequent quantification. A photo-degradation process of riboflavin was investigated by fluorescence spectroscopy and used as a model system. A two-step modeling approach, combining weighted PARAllel FACtor analysis (PARAFAC) with weighted non-linear regression of the known reaction kinetics, is suggested as a way of handling the fluorescence intensity shifts caused by the pH changes. The suggested strategy makes it possible to compensate for uncertainties in the shifted data and thereby obtain more reliable concentration profiles for the chemical compounds and kinetic parameters of the reaction.

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Wheat flour characterization using NIR and spectral filter based on Ant Colony Optimization

Ranzan

Strohm

Ranzan

et al. 2014

Chemometrics and Intelligent Laboratory Systems

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Evaluation of wavelength selection methods for 2D fluorescence spectra applied to bioprocesses characterization

Cited by 6 publications

References 26 publications

Application of Two-Dimensional Fluorescence Spectroscopy for the On-Line Monitoring of Teff-Based Substrate Fermentation Inoculated with Certain Probiotic Bacteria

Application of Two-Dimensional Fluorescence Spectroscopy for the On-Line Monitoring of Teff-Based Substrate Fermentation Inoculated with Certain Probiotic Bacteria

Weighted PARAFAC and Nonlinear Regression for Handling Intensity Changes in Fluorescence Spectroscopy Caused by pH Fluctuations

Wheat flour characterization using NIR and spectral filter based on Ant Colony Optimization

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