New Trends in the Valorisation of the Solid Fraction of Digestate for the Production of Value-Added Bioproducts

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🔬研究者:Provides a comprehensive overview of emerging valorization technologies and their barriers, useful for identifying research gaps in digestate bioprocessing.

🏢実務担当者:Offers insights into alternative digestate management strategies beyond land application, potentially reducing disposal costs and generating revenue from bioproducts.

🏛政策担当者:Highlights the need for regulatory harmonization and quality standards to support industrial uptake of digestate valorization within circular economy frameworks.

The rapid expansion of anaerobic digestion (AD) as a key technology for producing renewable energy has led to a substantial increase in digestate generation. This has intensified the need for sustainable management strategies that align with circular economy principles. While the solid fraction of digestate (SD) is traditionally applied to land or composted, its heterogeneous composition, regulatory constraints, and handling challenges restrict its wider use. This review aims to clarify the current state of SD treatment and highlight emerging opportunities to convert this underexploited resource into value-added bioproducts. A systematic bibliographic analysis of the past decade was conducted to identify consolidated and emerging SD valorisation technologies, supported by an evaluation of EU-level regulatory frameworks and the role of mechanical solid–liquid separation in enabling downstream valorisation. In addition, a comprehensive comparative table compiling physicochemical characterisation data of SD from various feedstocks and separation methods is presented, emphasising the significant variability in composition and its implications for valorisation pathways. The results show that, while composting and thermochemical routes, particularly pyrolysis, remain predominant, novel approaches such as advanced drying, pelletisation, vermicomposting, insect bioconversion, and fermentation-based pathways (including submerged and solid-state fermentation) are rapidly gaining interest. These emerging technologies enable the production of high-value products such as biochar, pellets, enzymes, microbial biopesticides, protein sources, and fungal biomass. However, their adoption is currently limited by feedstock heterogeneity, process complexity, scalability constraints, and economic considerations. Overall, SD is a versatile feedstock whose valorisation is expanding beyond agricultural applications. However, regulatory harmonisation, quality assurance, and process optimisation are still needed to encourage industrial uptake and to fully integrate SD into circular bioeconomy frameworks.

• semanticscholar https://www.mdpi.com/2227-9717/14/3/577/pdf?version=1770389591first seen 2026-07-16 07:03:20