{"title":"Enhancing Waste-Activated Sludge Valorisation Through Sequential Recovery of Polyhydroxyalkanoates and Extracellular Polymeric Substances","authors":"Antonio Mineo, Giorgio Mannina","doi":"10.1007/s10924-026-03953-w","DOIUrl":null,"url":null,"abstract":"<div><p>This study presents a coupled route for recovering intracellular polyhydroxyalkanoates (PHA) and extracellular polymeric substances (EPS) from waste-activated sludge. A direct accumulation approach was applied without prior microbial enrichment, using biomass collected from two membrane bioreactor (MBR) configurations: a conventional activated sludge MBR and a microalgae-sludge MBR. Both systems achieved comparable PHA accumulation kinetics and final contents, reaching approximately 31% (w/w) of volatile solids within 72 h. PHA was successfully extracted using a single-step process with the bio-based solvent 2-methyltetrahydrofuran, yielding recovery efficiencies of 62–66% and purities of around 65%, independent of sludge origin. The EPS were recovered from the acidified supernatant generated during biomass stabilisation, enabling partial precipitation and subsequent hydrogel formation, particularly for EPS derived from conventional sludge. The presence of microalgae significantly increased the overall EPS content but altered the polymer composition, thereby affecting hydrogel stability. The results demonstrate that sequential recovery of PHA and EPS is technically feasible and economically viable (< 0.5 € kg-1 PHA-EPS) within a single process train, without compromising PHA extraction performance. Further, results offer clear potential to improve the economic and resource efficiency of wastewater-based biopolymer production.</p></div>","PeriodicalId":659,"journal":{"name":"Journal of Polymers and the Environment","volume":"34 9","pages":""},"PeriodicalIF":5.6000,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10924-026-03953-w.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Polymers and the Environment","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s10924-026-03953-w","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
引用次数: 0
Abstract
This study presents a coupled route for recovering intracellular polyhydroxyalkanoates (PHA) and extracellular polymeric substances (EPS) from waste-activated sludge. A direct accumulation approach was applied without prior microbial enrichment, using biomass collected from two membrane bioreactor (MBR) configurations: a conventional activated sludge MBR and a microalgae-sludge MBR. Both systems achieved comparable PHA accumulation kinetics and final contents, reaching approximately 31% (w/w) of volatile solids within 72 h. PHA was successfully extracted using a single-step process with the bio-based solvent 2-methyltetrahydrofuran, yielding recovery efficiencies of 62–66% and purities of around 65%, independent of sludge origin. The EPS were recovered from the acidified supernatant generated during biomass stabilisation, enabling partial precipitation and subsequent hydrogel formation, particularly for EPS derived from conventional sludge. The presence of microalgae significantly increased the overall EPS content but altered the polymer composition, thereby affecting hydrogel stability. The results demonstrate that sequential recovery of PHA and EPS is technically feasible and economically viable (< 0.5 € kg-1 PHA-EPS) within a single process train, without compromising PHA extraction performance. Further, results offer clear potential to improve the economic and resource efficiency of wastewater-based biopolymer production.
期刊介绍：
The Journal of Polymers and the Environment fills the need for an international forum in this diverse and rapidly expanding field. The journal serves a crucial role for the publication of information from a wide range of disciplines and is a central outlet for the publication of high-quality peer-reviewed original papers, review articles and short communications. The journal is intentionally interdisciplinary in regard to contributions and covers the following subjects - polymers, environmentally degradable polymers, and degradation pathways: biological, photochemical, oxidative and hydrolytic; new environmental materials: derived by chemical and biosynthetic routes; environmental blends and composites; developments in processing and reactive processing of environmental polymers; characterization of environmental materials: mechanical, physical, thermal, rheological, morphological, and others; recyclable polymers and plastics recycling environmental testing: in-laboratory simulations, outdoor exposures, and standardization of methodologies; environmental fate: end products and intermediates of biodegradation; microbiology and enzymology of polymer biodegradation; solid-waste management and public legislation specific to environmental polymers; and other related topics.
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