Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli

IntroductionAgro-industrial wastes are generated in huge amounts triggering damages to the environment and human health. Therefore, there is an urgent necessity for its revalorisation into high-value compounds, including biofuels. One such wastes is the brewer's spent grain (BSG), a by-product...

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Main Authors: Gema Cabrera, José Manuel Jáimez, Jezabel Sánchez-Oneto, Jorge Bolivar, Antonio Valle
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-11-01
Series:Frontiers in Bioengineering and Biotechnology
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Online Access:https://www.frontiersin.org/articles/10.3389/fbioe.2024.1473704/full
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author Gema Cabrera
Gema Cabrera
José Manuel Jáimez
Jezabel Sánchez-Oneto
Jezabel Sánchez-Oneto
Jorge Bolivar
Jorge Bolivar
Antonio Valle
Antonio Valle
author_facet Gema Cabrera
Gema Cabrera
José Manuel Jáimez
Jezabel Sánchez-Oneto
Jezabel Sánchez-Oneto
Jorge Bolivar
Jorge Bolivar
Antonio Valle
Antonio Valle
author_sort Gema Cabrera
collection DOAJ
description IntroductionAgro-industrial wastes are generated in huge amounts triggering damages to the environment and human health. Therefore, there is an urgent necessity for its revalorisation into high-value compounds, including biofuels. One such wastes is the brewer's spent grain (BSG), a by-product of the beer industry, which is produced in vast quantities worldwide. The rich-fibre and protein content of BSG makes this waste a valuable resource for biotechnological applications, although the main challenge of this approach is to make the carbohydrates and proteins available for bacterial metabolisation into high-value products. This work aims to optimise a thermal-hydrolysis process to revalorise BSG by bacterial conversion into hydrogen (H2), as a clean energy that can replace fossil fuels.MethodsA 2k full factorial design method was employed hydrolysation of BSG and showed that temperature and acid concentration are significant factors that affect the extraction of reducing sugars (RS) and proteins. Subsequently, steepest ascent and central composite design (CCD) statistical methods were applied to determine the optimal conditions for hydrolysis.ResultsThe optimised hydrolysis condition were 0.047 M H2SO4, 150°C, 30 min and 15% BSG, leading to the theoretical concentrations of 54.8 g RS/L and 20 g/L proteins. However, 5'-hydroxymethylfurfural (HMF) was generated in thermal-hydrolysis conditions at higher temperatures exceeding 132°C. Therefore, a screening of HBSGs fermentation using Escherichia coli was conducted in order to identify the most suitable conditions for maximizing H2, as well as the production of volatile fatty acids (succinate and acetate) and ethanol. Among the tested conditions, HBSG A17 (117°C, 20 min, and 0.1 M H2SO4) yielded the highest H2 production of 48 mmol/L in this work.ConclusionThis study provides valuable insights into the optimisation of BSG pre-treatment for biotechnological applications, which may help in the selection of the most appropriate hydrolysis conditions based on the desired end product.
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spelling doaj-art-df410894f66e402ca28bbd080c78678f2025-08-20T02:23:46ZengFrontiers Media S.A.Frontiers in Bioengineering and Biotechnology2296-41852024-11-011210.3389/fbioe.2024.14737041473704Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coliGema Cabrera0Gema Cabrera1José Manuel Jáimez2Jezabel Sánchez-Oneto3Jezabel Sánchez-Oneto4Jorge Bolivar5Jorge Bolivar6Antonio Valle7Antonio Valle8Department of Chemical Engineering and Food Technology, Campus Universitario de Puerto Real, University of Cadiz, Cadiz, SpainInstitute of Viticulture and Agri-Food Research (IVAGRO), International Campus of Excellence (ceiA3), University of Cadiz, Cadiz, SpainDepartment of Chemical Engineering and Food Technology, Campus Universitario de Puerto Real, University of Cadiz, Cadiz, SpainDepartment of Chemical Engineering and Food Technology, Campus Universitario de Puerto Real, University of Cadiz, Cadiz, SpainInstitute of Viticulture and Agri-Food Research (IVAGRO), International Campus of Excellence (ceiA3), University of Cadiz, Cadiz, SpainDepartment of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Cadiz, SpainInstitute of Biomolecules (INBIO), University of Cadiz, Cadiz, SpainInstitute of Viticulture and Agri-Food Research (IVAGRO), International Campus of Excellence (ceiA3), University of Cadiz, Cadiz, SpainDepartment of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Cadiz, SpainIntroductionAgro-industrial wastes are generated in huge amounts triggering damages to the environment and human health. Therefore, there is an urgent necessity for its revalorisation into high-value compounds, including biofuels. One such wastes is the brewer's spent grain (BSG), a by-product of the beer industry, which is produced in vast quantities worldwide. The rich-fibre and protein content of BSG makes this waste a valuable resource for biotechnological applications, although the main challenge of this approach is to make the carbohydrates and proteins available for bacterial metabolisation into high-value products. This work aims to optimise a thermal-hydrolysis process to revalorise BSG by bacterial conversion into hydrogen (H2), as a clean energy that can replace fossil fuels.MethodsA 2k full factorial design method was employed hydrolysation of BSG and showed that temperature and acid concentration are significant factors that affect the extraction of reducing sugars (RS) and proteins. Subsequently, steepest ascent and central composite design (CCD) statistical methods were applied to determine the optimal conditions for hydrolysis.ResultsThe optimised hydrolysis condition were 0.047 M H2SO4, 150°C, 30 min and 15% BSG, leading to the theoretical concentrations of 54.8 g RS/L and 20 g/L proteins. However, 5'-hydroxymethylfurfural (HMF) was generated in thermal-hydrolysis conditions at higher temperatures exceeding 132°C. Therefore, a screening of HBSGs fermentation using Escherichia coli was conducted in order to identify the most suitable conditions for maximizing H2, as well as the production of volatile fatty acids (succinate and acetate) and ethanol. Among the tested conditions, HBSG A17 (117°C, 20 min, and 0.1 M H2SO4) yielded the highest H2 production of 48 mmol/L in this work.ConclusionThis study provides valuable insights into the optimisation of BSG pre-treatment for biotechnological applications, which may help in the selection of the most appropriate hydrolysis conditions based on the desired end product.https://www.frontiersin.org/articles/10.3389/fbioe.2024.1473704/fullbrewer’s spent grainbiohydrogenEscherichia colidesign of experimentdark fermentation
spellingShingle Gema Cabrera
Gema Cabrera
José Manuel Jáimez
Jezabel Sánchez-Oneto
Jezabel Sánchez-Oneto
Jorge Bolivar
Jorge Bolivar
Antonio Valle
Antonio Valle
Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli
Frontiers in Bioengineering and Biotechnology
brewer’s spent grain
biohydrogen
Escherichia coli
design of experiment
dark fermentation
title Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli
title_full Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli
title_fullStr Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli
title_full_unstemmed Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli
title_short Revalorisation of brewer’s spent grain for biotechnological production of hydrogen with Escherichia coli
title_sort revalorisation of brewer s spent grain for biotechnological production of hydrogen with escherichia coli
topic brewer’s spent grain
biohydrogen
Escherichia coli
design of experiment
dark fermentation
url https://www.frontiersin.org/articles/10.3389/fbioe.2024.1473704/full
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