Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants

The secondary sludge of wastewater treatment plants is an abundant and problematic bacterial biomass that accumulates nutrients from wastewater, mainly as proteins and carbohydrates. Recent studies have focused on energy recovery of this biomass by anaerobic digestion to produce biogas. However, fra...

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Main Authors: Angel Alejandro Filipigh, Elena M. Rojo, Andrea Natalia Pila, Silvia Bolado
Format: Article
Language:English
Published: Elsevier 2024-11-01
Series:Chemical Engineering Journal Advances
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666821124001030
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author Angel Alejandro Filipigh
Elena M. Rojo
Andrea Natalia Pila
Silvia Bolado
author_facet Angel Alejandro Filipigh
Elena M. Rojo
Andrea Natalia Pila
Silvia Bolado
author_sort Angel Alejandro Filipigh
collection DOAJ
description The secondary sludge of wastewater treatment plants is an abundant and problematic bacterial biomass that accumulates nutrients from wastewater, mainly as proteins and carbohydrates. Recent studies have focused on energy recovery of this biomass by anaerobic digestion to produce biogas. However, fractional recovery of the sludge components could increase its value and provide the basis for a biorefinery based on this waste. Since ≈ 40-60% of the bacterial dry weight is protein, this biomass could be an important source of functional peptides or amino acids, and the carbohydrates could be used to produce bioplastics or biofuels. This study compares chemical, physical and biological hydrolysis methods and their sequential and assisted combinations to recover proteins and carbohydrates from sludge. Ultrasound-assisted alkaline treatment provided the highest protein solubilization yield (97.2%) with low degradation, resulting in peptide recovery yields of 75.1% with sizes from 70-215 kDa, 40% of essential amino acids and purity of 35.3% with NaOH 1M. The hydrothermal-alkaline combination almost completely solubilized the proteins but not the carbohydrates (77.4%) with high degradation (52.6%). The hydrothermal-acidic combination achieved high carbohydrate solubilization (94%) and recoveries of glucose (63.6%) and xylose (12.6%) but low protein recovery (43.7%) as small size peptides.
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spelling doaj-art-6d68a21a143446eda0cada77e4bac5e02024-12-04T05:14:44ZengElsevierChemical Engineering Journal Advances2666-82112024-11-0120100686Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plantsAngel Alejandro Filipigh0Elena M. Rojo1Andrea Natalia Pila2Silvia Bolado3Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, SpainDepartment of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, SpainInstitute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, SpainDepartment of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Corresponding author at: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain.The secondary sludge of wastewater treatment plants is an abundant and problematic bacterial biomass that accumulates nutrients from wastewater, mainly as proteins and carbohydrates. Recent studies have focused on energy recovery of this biomass by anaerobic digestion to produce biogas. However, fractional recovery of the sludge components could increase its value and provide the basis for a biorefinery based on this waste. Since ≈ 40-60% of the bacterial dry weight is protein, this biomass could be an important source of functional peptides or amino acids, and the carbohydrates could be used to produce bioplastics or biofuels. This study compares chemical, physical and biological hydrolysis methods and their sequential and assisted combinations to recover proteins and carbohydrates from sludge. Ultrasound-assisted alkaline treatment provided the highest protein solubilization yield (97.2%) with low degradation, resulting in peptide recovery yields of 75.1% with sizes from 70-215 kDa, 40% of essential amino acids and purity of 35.3% with NaOH 1M. The hydrothermal-alkaline combination almost completely solubilized the proteins but not the carbohydrates (77.4%) with high degradation (52.6%). The hydrothermal-acidic combination achieved high carbohydrate solubilization (94%) and recoveries of glucose (63.6%) and xylose (12.6%) but low protein recovery (43.7%) as small size peptides.http://www.sciencedirect.com/science/article/pii/S2666821124001030BiorefineryPeptide sizeHydrolysisMonosaccharideSludge valorizationAmino acids
spellingShingle Angel Alejandro Filipigh
Elena M. Rojo
Andrea Natalia Pila
Silvia Bolado
Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
Chemical Engineering Journal Advances
Biorefinery
Peptide size
Hydrolysis
Monosaccharide
Sludge valorization
Amino acids
title Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
title_full Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
title_fullStr Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
title_full_unstemmed Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
title_short Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
title_sort fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants
topic Biorefinery
Peptide size
Hydrolysis
Monosaccharide
Sludge valorization
Amino acids
url http://www.sciencedirect.com/science/article/pii/S2666821124001030
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