Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration

This study explores the impact of initial substrate concentrations on biomass growth, hydrogen production, and acid generation during acidogenic fermentation of a synthetic fruit juice wastewater. Four substrate concentrations, within the range 0.30–2.12 C mol·L<sup>−1</sup>, were tested...

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Main Authors: Encarnación Díaz Domínguez, María Eugenia Ibañez López, José Luis García Morales, Ester López-Fernández, Francisco Jesús Fernández-Morales
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/14/22/10519
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author Encarnación Díaz Domínguez
María Eugenia Ibañez López
José Luis García Morales
Ester López-Fernández
Francisco Jesús Fernández-Morales
author_facet Encarnación Díaz Domínguez
María Eugenia Ibañez López
José Luis García Morales
Ester López-Fernández
Francisco Jesús Fernández-Morales
author_sort Encarnación Díaz Domínguez
collection DOAJ
description This study explores the impact of initial substrate concentrations on biomass growth, hydrogen production, and acid generation during acidogenic fermentation of a synthetic fruit juice wastewater. Four substrate concentrations, within the range 0.30–2.12 C mol·L<sup>−1</sup>, were tested using a mixed acidogenic bacterial culture. Batch reactors were employed to conduct the study, and the results were analyzed to determine inhibition effects. The highest hydrogen production (6.1 L H<sub>2</sub>·substrate C mol<sup>−1</sup>) and hydrogen percentage in the gas phase (57%) were achieved at a substrate concentration of 0.30 C mol·L<sup>−1</sup>. Higher substrate concentrations reduced the hydrogen production due to substrate and product inhibition events. The maximum H<sub>2</sub> potential production was 4.15 Nm<sup>3</sup>/m<sup>3</sup> reactor at a substrate concentration of 0.91 C mol·L<sup>−1</sup>. Biomass growth and VFA production followed exponential trends at low substrate concentrations, 0.30 and 0.091 C mol·L<sup>−1</sup>, while high concentrations resulted in linear trends due to inhibition effects caused by the substrate. The main acids produced were lactic at low concentrations, and acetic when dealing with high concentrations. The highest final acid concentrations were obtained with the highest initial substrate concentration, but their yields were significantly lower due to the substrate and product inhibitions experienced by the biomass.
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spelling doaj-art-dac424c50fda455fb651592b1c0880ee2025-08-20T01:53:49ZengMDPI AGApplied Sciences2076-34172024-11-0114221051910.3390/app142210519Dark Fermentation of Fruit Juice Effluents: Effects of Substrate ConcentrationEncarnación Díaz Domínguez0María Eugenia Ibañez López1José Luis García Morales2Ester López-Fernández3Francisco Jesús Fernández-Morales4Department of Environmental Technologies, Faculty of Marine and Environmental Sciences, IVAGRO-Wine and Agrifood Research Institute, University of Cadiz, 11510 Cadiz, SpainDepartment of Environmental Technologies, Faculty of Marine and Environmental Sciences, IVAGRO-Wine and Agrifood Research Institute, University of Cadiz, 11510 Cadiz, SpainDepartment of Environmental Technologies, Faculty of Marine and Environmental Sciences, IVAGRO-Wine and Agrifood Research Institute, University of Cadiz, 11510 Cadiz, SpainDepartment of Chemical Engineering, University of Castilla-La Mancha, Avda. Camilo José Cela S/N, 13071 Ciudad Real, SpainDepartment of Chemical Engineering, University of Castilla-La Mancha, Avda. Camilo José Cela S/N, 13071 Ciudad Real, SpainThis study explores the impact of initial substrate concentrations on biomass growth, hydrogen production, and acid generation during acidogenic fermentation of a synthetic fruit juice wastewater. Four substrate concentrations, within the range 0.30–2.12 C mol·L<sup>−1</sup>, were tested using a mixed acidogenic bacterial culture. Batch reactors were employed to conduct the study, and the results were analyzed to determine inhibition effects. The highest hydrogen production (6.1 L H<sub>2</sub>·substrate C mol<sup>−1</sup>) and hydrogen percentage in the gas phase (57%) were achieved at a substrate concentration of 0.30 C mol·L<sup>−1</sup>. Higher substrate concentrations reduced the hydrogen production due to substrate and product inhibition events. The maximum H<sub>2</sub> potential production was 4.15 Nm<sup>3</sup>/m<sup>3</sup> reactor at a substrate concentration of 0.91 C mol·L<sup>−1</sup>. Biomass growth and VFA production followed exponential trends at low substrate concentrations, 0.30 and 0.091 C mol·L<sup>−1</sup>, while high concentrations resulted in linear trends due to inhibition effects caused by the substrate. The main acids produced were lactic at low concentrations, and acetic when dealing with high concentrations. The highest final acid concentrations were obtained with the highest initial substrate concentration, but their yields were significantly lower due to the substrate and product inhibitions experienced by the biomass.https://www.mdpi.com/2076-3417/14/22/10519acidogenic fermentationhydrogen productionvolatile fatty acidsinhibition
spellingShingle Encarnación Díaz Domínguez
María Eugenia Ibañez López
José Luis García Morales
Ester López-Fernández
Francisco Jesús Fernández-Morales
Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration
Applied Sciences
acidogenic fermentation
hydrogen production
volatile fatty acids
inhibition
title Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration
title_full Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration
title_fullStr Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration
title_full_unstemmed Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration
title_short Dark Fermentation of Fruit Juice Effluents: Effects of Substrate Concentration
title_sort dark fermentation of fruit juice effluents effects of substrate concentration
topic acidogenic fermentation
hydrogen production
volatile fatty acids
inhibition
url https://www.mdpi.com/2076-3417/14/22/10519
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AT mariaeugeniaibanezlopez darkfermentationoffruitjuiceeffluentseffectsofsubstrateconcentration
AT joseluisgarciamorales darkfermentationoffruitjuiceeffluentseffectsofsubstrateconcentration
AT esterlopezfernandez darkfermentationoffruitjuiceeffluentseffectsofsubstrateconcentration
AT franciscojesusfernandezmorales darkfermentationoffruitjuiceeffluentseffectsofsubstrateconcentration