Abstract
ENCAPSULATE project deals with the development of innovative and highly efficient catalytic processes for the fractionation and in-situ upgrading of second-generation lignocellulosic biomass (L-Bio) toward both highly delignified cellulose, valuable polyols and sugars (e.g. xylitol, sorbitol, mannitol and glucose) and lignin oil (LO). L-Bio is known to be the most abundant non-food, waste biopolymer available on earth, therefore representing the most promising feedstock to meet the criteria of a more sustainable circular economy. Noteworthy, ENCAPSULATE aims to promote a straightforward, well-rounded approach toward the sustainable valorization of all the three main components of L-Bio. In particular, the fractionation process will be performed in the presence of advanced, easily separable and recyclable heterogeneous catalysts following two main approaches, which represent the state of the art of these kinds of processes: the Reductive Catalytic Fractionation (RCF) and the acid catalyzed organosolv reaction with organic carbonates/glycols mixtures (OCS). In this way, a high purity cellulose (CE) solid fraction can be recovered and further valorized through two main strategies: i) by promoting a consecutive depolymerization towards sugars (glucose) and/or related polyols (sorbitol and mannitol), valuable products for the sweeteners and special polymers sectors or ii) to produce green materials for the removal of organic and inorganic pollutants from wastewater and to be used as supports for flow catalytic processes. Particular attention will be paid in the valorization of hemicellulose (HE): for instance, whenever possible, its depolymerisation via hydrolysis/hydrogenolysis will be promoted in-situ during the fractionation step, in this way recovering highly valuable sugars and polyols for the sweetening sector (i.e. xylose and xylitol) and finally limiting the downstream processes of the herein proposed supply chain. Finally, complex mixtures of LO are expected to be achieved during the fractionation stage. These mixtures will be deeply characterized via GPC, 2D-NMR, 2D-HSQC, 31P-NMR, DSC and TGA analyses and further split into suitable sections depending on the molecular weight through the state of art of separation technologies. In this way, while the low and high weight lignin will be used for the preparation of capsules for the delivery of active ingredients, of nanoparticles for water remediation purposes, and of nanolubricants; the medium weight LO will be further treated through a catalytic depolymerisation process with the final aim to achieve high valuable bio-based phenolics. To sum up, ENCAPSULATE opens the way to the innovative, comprehensive valorization of low valuable L-Bio, ranging from pruning residues of urban trees to agriculture and forestry wastes, by advanced novel technologies, with a particular focus to catalyst recyclability. Achieved Results ENCAPSULATE combined catalyst development, biomass fractionation, polysaccharide valorization, water treatment applications, and lignin upgrading, generating a coherent portfolio of scientific and technological achievements. 1.A broad family of heterogeneous catalysts was successfully synthesized and characterized, including acidic phosphates, layered mixed oxides, zeolites, sulfonated carbons, and supported noble-metal catalysts. Comprehensive structural and physicochemical characterization confirmed the successful preparation of materials with tailored acidity, porosity, surface area, and metal dispersion. The project established relationships between catalyst structure and catalytic performance, providing a valuable basis for future biomass-conversion technologies. A particularly significant achievement was the development of recyclable magnetic catalysts for RCF. These catalysts, based on Ru or Pd supported on γ-Fe₂O₃ (maghemite), maintained high catalytic activity while enabling straightforward magnetic separation from reaction mixtures, overcoming one of the major limitations of conventional Ru/C systems. 2.Improved RCF of L-Bio: the project optimized catalytic fractionation processes for 2nd generation L-Bio, with a focus on poplar-derived feedstocks. Novel magnetic catalysts were applied to RCF processes, enabling efficient lignin depolymerization while preserving the carbohydrate fraction. Compared with conventional carbon-supported catalysts, the magnetic catalysts offered a major practical advantage: catalyst recovery efficiencies of approximately 95 wt%, whereas recovery of Ru/C catalysts remained below 10 wt% because of catalyst entrapment within cellulose fibers. This result represents a major step toward industrially viable and circular biomass fractionation technologies. The project also generated a deeper understanding of catalyst stability, recyclability, and reaction mechanisms, helping to establish the foundations for scalable lignin-first biorefinery concepts. 3.A systematic investigation of carbohydrate conversion pathways was carried out, progressing from model compounds such as glucose and cellobiose to real cellulose fractions obtained after RCF treatment. Optimized hydrolysis and hydrogenolysis routes were developed for the production of sugars and sugar-derived polyols. The project identified suitable acidic catalysts and reaction conditions capable of promoting efficient depolymerization of polysaccharides while minimizing degradation pathways. These studies demonstrated the feasibility of transforming cellulose-rich residues into value-added platform molecules, contributing to the complete utilization of all biomass fractions rather than focusing exclusively on lignin valorization. 4.Development of cellulose-based hybrid materials: innovative cellulose-based hybrid materials incorporating zero-valent iron nanoparticles (nZVI) were prepared. The project identified critical challenges associated with iron oxidation and developed stabilization strategies based on cellulose supports, citrate complexation, and cotton-derived matrices. The resulting composite films exhibited improved structural integrity and enhanced resistance to nanoparticle oxidation. Long-term leaching studies demonstrated limited release of active species, indicating good material stability and suitability for environmental applications. 5.One of the most impactful outcomes of the project was the development of biomass-derived materials for water treatment. Cellulose/nZVI composite films successfully reduced 4-nitrophenol, a common organic pollutant, achieving rapid pollutant removal and conversion to less harmful products. Removal efficiencies above 90% were achieved within only a few minutes, demonstrating the high catalytic activity of the developed materials. The films also maintained functionality during recycling tests, confirming their potential for repeated use. In parallel, lignin nanoparticles obtained from RCF lignin were combined with cellulose matrices to produce multifunctional composites for wastewater remediation. These materials showed promising adsorption and photocatalytic degradation properties toward model contaminants such as methylene blue and pharmaceutical pollutants, highlighting the possibility of converting biorefinery side streams into high-value environmental technologies. 6.Extensive analytical characterization of LO produced under different catalytic conditions was performed using elemental analysis, GPC, HSQC NMR, and 31P NMR. These studies revealed how catalyst type influences lignin molecular structure, hydrogen content, functional-group distribution, and molecular-weight profiles. The resulting knowledge provided crucial insights into lignin depolymerization pathways and the generation of lignin-derived intermediates suitable for further upgrading. 7.The project demonstrated that lignin can be transformed into advanced functional materials rather than being treated as a low-value by-product. RCF lignin was successfully converted into microcapsules for active-ingredient delivery and into lignin nanoparticles with controlled morphology and functionality. These materials showed potential for encapsulation technologies, controlled release systems, and environmental remediation applications. Furthermore, lignin-derived nanolubricants and sustainable nanoparticle platforms were developed, expanding the application range of renewable aromatic materials. 8.Synthesis of bio-phenolics and mechanistic insights: the project investigated the upgrading of intermediate lignin-oil fractions into bio-based phenolic compounds. Through studies on model molecules and real lignin-derived streams, important mechanistic insights were obtained regarding hydrogenolysis (e.g. selective cleavage of β-O-4 linkages), hydrodeoxygenation (HDO), aromatic rings hydrogenation (HYD) and acidolysis (via heterogeneously catalysed OCS). These results provide a foundation for the future production of renewable phenolic chemicals, polymers, fuel additives, and specialty chemicals from lignin, contributing to the full valorization of biomass-derived aromatic fractions. 9.Scientific Impact: the project generated a strong scientific output, including multiple peer-reviewed publications in high-impact journals such as ACS Sus. Chem. Eng., ChemSusChem, and Faraday Discussions (in addition to other two publications in preparation), together with numerous oral and poster presentations at international conferences. The results strengthened collaboration between the University of Bologna and Ca’ Foscari University of Venice and contributed significantly to the advancement of sustainable biorefinery research. Overall, ENCAPSULATE successfully demonstrated an integrated platform for converting L-Bio into renewable chemicals, functional materials, environmental remediation technologies, and lignin-derived specialty products, while simultaneously addressing key challenges related to catalyst recovery, process sustainability, and full biomass utilization.
Dettagli del progetto
Responsabile scientifico: Tommaso Tabanelli
Strutture Unibo coinvolte:
Dipartimento di Chimica Industriale "Toso Montanari"
Coordinatore:
ALMA MATER STUDIORUM - Università di Bologna(Italy)
Contributo totale di progetto: Euro (EUR) 219.869,00
Contributo totale Unibo: Euro (EUR) 127.669,00
Durata del progetto in mesi: 24
Data di inizio
28/09/2023
Data di fine:
27/09/2025
