This study presents a multiscale investigation of mycelium-based biocomposites produced via solid-state cultivation of Ganoderma lucidum on agro-food sidestreams. Three lignocellulosic residues, wheat bran (in two particle sizes), rice straw, and spent coffee grounds, were selected based on global availability and chemical diversity. The biocomposites were characterized to investigate how substrate composition and mycelial growth influence microstructure and macroscopic performance. Monosaccharide analysis and scanning electron microscopy (SEM) revealed that wheat bran supported enhanced mycelial growth. Fine wheat bran-based composites exhibited compressive strengths up to 449 kPa at 30 % strain and tensile moduli of 15–25 MPa, significantly higher than expanded polystyrene (EPS), a conventional insulator. All biocomposites showed intrinsic surface hydrophobicity (water contact angles of 106–120°). Thermal analyses, including thermogravimetric analysis (TGA) and hot-plate conductivity measurement, confirmed their suitability as porous insulation. Cone calorimetry demonstrated improved fire safety in wheat bran-based composites, with reduced peak heat release rates (112–115 kW/m2). Embodied energy and carbon footprint assessments indicated up to 89 % lower energy demand and 72 % lower CO2 emissions compared with EPS. Through multiscale characterization and direct benchmarking, this study shows how substrate selection and fungal-substrate interactions can be utilized to tailor performance. The findings provide insights into converting low-value biomass into scalable, fire-safer, and environmentally responsible insulation materials. 

Bioelectrochemical systems (BES) have emerged as sustainable platforms for CO2 valorisation and renewable energy production, but their efficiency is often limited by slow biocathode start-up. A promising route to create more efficient BES is the use of removable hydrogels to improve microbial adhesion. In this work, the influence of new coating biocathodes on poly(ethylene oxide) hydrogels for improved bioelectrochemical systems was evaluated. Hydrogels with different concentrations of poly(ethylene oxide) (5, 10, and 15 wt %) were evaluated as electrode coating. In addition, their effect on initial cell adhesion, microbial proliferation and productivity were studied. The results showed that 10 wt % PEO produced the most suitable coating, combining homogeneous pore structure, adequate elastic modulus and controlled detachment within 5 days. When applied to pretreated carbon felt, the hydrogel increased current density by 37.4% compared with uncoated electrodes, accelerated the start-up period, and promoting higher methane production. At steady state, the hydrogel-coated biocathode directed more carbon into methane (26 vs 3% respect to control) and reduced the unconverted carbon fraction (41 vs 65% respect to control). Microbial community analysis revealed selective enrichment of Methanobacterium, indicating a hydrogenotrophic pathway consistent with the applied potential. In conclusion, this study has made it possible to improve the start-up of the bioelectrochemical systems, demonstrating the potential of hydrogels in the start-up of these systems. 

Developing biodegradable menstrual products using co-stream proteins as a material alternative to fossil counterparts presents a significant environmental advantage across their entire value chain. The intrinsic properties of wheat gluten foams derived from wheat starch production have been validated with respect to their potential as absorbent core layers in disposable sanitary pads, which is relevant to the rising demand for eco-friendly disposable sanitary pad alternatives. Here, we report the fabrication of a gluten-porous absorbent layer and evaluate its liquid absorption properties and mechanical stability under relevant operating conditions compared to a commercial absorbent foam layer used in sanitary pads. The porosity was achieved using sodium and ammonium bicarbonate, which are non-toxic and food-grade blowing agents, and the materials were shaped/foamed using a conventional oven. The use of sodium bicarbonate resulted in a more homogeneous and lower-density foam with smaller pores than with ammonium bicarbonate. The developed prototypes show comparable mechanical properties under compression to foams used in commercial pads, retaining up to 95% of their initial shape after 3 h of compression. Moreover, the foamed structure permitted a liquid uptake of saline and blood of 4.5 g g−1 and 1 g g−1, respectively, with the possibility to absorb up to 1.5 g g−1 of saline under load. The results indicate that the choice of blowing agent has a large impact on the performance of gluten pads under constant pressure. It is thereby demonstrated here that protein-based foams have adequate mechanical and absorption properties that make them interesting for their future use as the absorbent layer in sanitary products following a circular economy model.

Water-soluble polymers are materials rapidly growing in volume and in number of materials and applications. Examples include synthetic plastics such as polyacrylamide, polyacrylic acid, polyethylene glycol, polyethylene oxide and polyvinyl alcohol, with applications ranging from cosmetics and paints to water purification, pharmaceutics and food packaging. Despite their abundance, their environmental concerns (e.g., bioaccumulation, toxicity, and persistence) are still not sufficiently assessed, especially since water soluble plastics are often not biodegradable, due to their chemical structure. This review aims to overview the most important water-soluble and biodegradable polymers, their applications, and their environmental impact. Degradation products from water-insoluble polymers designed for biodegradation can also be water soluble. Most water-soluble plastics are not immediately harmful for humans and the environment, but the degradation products are sometimes more hazardous, e.g. for polyacrylamide. An increased use of water-soluble plastics could also introduce unanticipated environmental hazards. Therefore, excessive use of water-soluble plastics in applications where they can enter the environment should be discouraged. Often the plastics can be omitted or replaced by natural polymers with lower risks. It is recommended to include non-biodegradable water-soluble plastics in regulations for microplastics, to make risk assessments for different water-soluble plastics and to develop labels for flushable materials.

Sustainable technologies have enabled the production of degradable single-use plastics (SUPs) for various applications. However, environmentally friendly, porous disposable absorbents still lack the competitive functionality of synthetic options. In this work, we report the continuous extrusion of fully biopolymer-based porous absorbents derived from integrated proteins and lignocellulosic residues, all sourced from biomass waste. The results show that the saline absorption capacity of the extruded materials increases 1.5 times compared to the reference solely by including oat husk, a lignocellulosic byproduct from the food industry. The absorption was further improved 2 times by including a delignification step on the oat husk and wheat bran, demonstrating the importance of the biomass’s chemistry in increasing the material’s absorption. Here, the addition of 20 wt % of Keratin fibers from food waste increases the material’s absorbency to 6.5 g/g, with the ability to retain 2 g/g of the saline solution in its structure, which is also the highest reported value for extruded protein-based formulations so far. This work advances the development of porous absorbent materials with competitive performance, utilizing industrial methods and upcycling undervalued biomass waste into sustainable consumer products. Introducing porous biopolymer-based materials as alternatives to synthetic counterparts used in the hygiene and sanitary industries ensures the return of safe molecules to nature, paving the way for microplastic-free, single-use, porous absorbents.

A key challenge for implementation of a circular economy model in manufacturing systems is the functional dependence of downstream processes on upstream byproducts. Design principles provide a framework for mapping goals to solutions by decomposing complex engineering problems into structured sets of requirements to be satisfied and embodied by design parameters and process variables. Large Language Models can computationally represent such textually-described design elements to quantify interconnections between problems, solutions, and processes. We present a Functional Digital Twin concept, powered by AI language modeling and guided by principles of manufacturing systems design, to identify functionally coupled process variables in an industrial symbiosis and automatically push alerts to stakeholders in a circular manufacturing system. Changes in byproduct composition are pushed downstream, and upstream decision-makers are guided to balance satisfying their design requirements with maintaining circularity of the system. The presented method is demonstrated in a case study of bio-based absorbent materials for intended use in disposable sanitary articles developed from byproducts of the agro-food industry.

Protein-based absorbent materials exhibit significant limitations in water retention compared to synthetic superabsorbent polymers (SAPs), widely used in agriculture, hygiene, and biomedical applications. Recent investigations have focused on leveraging highly soluble charged proteins such as patatin (a glycoprotein derived from potatoes) as natural alternatives to synthetic SAPs, given their unique structural properties and the opportunity they provide as sustainable raw material alternatives. This study investigates how the intrinsic amino acid composition and charged residues of patatin can be modified through mutagenesis to tailor its superabsorbent properties. Here, patatin was expressed in Escherichia coli to improve the water absorption capacity by altering its amino acid composition. By increasing liquid accessibility and charge density, our method of altering the charged profile of the protein significantly enhances the protein's swelling capacity, doubling its absorption compared to native patatin. Additionally, molecular dynamics simulations reveal that protein variants enriched with lysine and aspartic acid facilitate increased hydrogen bonding interactions with water molecules, thereby enhancing hydration. These results provide a fundamental understanding of how to tailor the physicochemical nature of proteins to develop them as viable bio-based absorbents for advanced sanitary applications, combining material science and biotechnology.

This study explores the dual challenge of enhancing the properties of protein-based foams produced from agricultural by-products through the incorporation of red mud waste from alumina production. Foams were manufactured using an extrusion process, employing gluten and zein proteins, with raw red mud and its oxalic acid leachates serving as additives. A factorial design was utilized to assess the significance of various parameters on the mechanical properties of materials. The results indicate that red mud-based additives do not improve foam mechanical stability in terms of stiffness (as measured by Young's modulus) and thus do not function effectively to form short crosslinking bridges. However, the results show red mud serves mainly as a plasticizer and reducing/oxidizing agent, while also potentially enhancing the formation of long crosslinking bridges. This is evidenced by a significant increase in foam strain when red mud powder is extruded with gluten, reaching 190% strain at break and densities between 500 and 1500 kg/m³. Consequently, red mud shows potential to be repurposed as an additive in protein-based foams, suitable for applications requiring elastic deformation while keeping a stable porous structure manufactured via continuous extrusion.

Protein nanofibrils (PNFs), especially those from the whey protein β-lactoglobulin, hold the promise for applications in food technology, medicine, and sustainable materials. In this work, we explore the mechanisms underlying the sol-gel transition of whey protein isolate triggered by pre-fragmented whey fibrils (seeds) at low pH and high temperature. We show that, under these conditions, the formed hydrogels are constructed from PNFs. The presented results suggest that the seeds amplify the fibril growth process by providing active ends that capture peptide monomers produced via acid hydrolysis. This changes the fibrils' length distribution (up to 10-fold increase of their average contour length), and the samples reach the percolation threshold at a much lower mass concentration of fibrils. We also note that seeding has a strong impact on morphology and catalyzes a conversion of short, curved fibrils into long straight ones, which also contribute to the lower percolation limit. Rheological measurements indicate that attractive inter-fibrillar forces stabilize the PNF network. This is further evidenced by the gels’ resistance to disassembly across a wide pH range, implying that other forces than electrostatics are important for stabilizing the fibrillar network. Finally, we discuss the nature of the sol-gel transition based on continuum percolation theory, which corroborates the observed relationship between PNF length distribution and the sol-gel transition.

Mycelium derived from Ganoderma lucidum was employed as a template for synthesising silicon oxide (SiOx) nanofibers. The intricate structures of mycelial hyphae fibrils were replicated with high precision using an inexpensive commercial silane (3-aminopropyl)-triethoxysilane (APTES). Following the removal of the organic mycelium template phase at 600 degrees C, APTES was successfully converted to SiOx. The resulting SiOx fibres retained the morphology of the mycelium template, with a nearly identical fibre density to the original fibrous network. A fibril diameter reduction of approximately 43% was observed from 603 to 344 nm. All synthesised materials exhibited coherent structural integrity, sufficient for handling without breakage, although they were notably less mechanically flexible than the original mycelium template. The novel hybrid mycelium-3-aminopropyl-silsesquioxane fibre network and the thermally converted SiOx network displayed notable liquid absorption properties. These materials allowed for the preferential absorption of oil or water, depending on the presence of the amino group functionality. Remarkably, the SiOx network rapidly absorbed methylene blue-dyed water within 400 ms, demonstrating behaviour opposite to the virgin mycelium network. Additionally, the materials exhibited high thermal stability, withstanding flame exposure at approximately 1400 degrees C while maintaining their nano/micromorphology. This innovative approach of using "living" templates expands the range of morphologies that can be replicated in inorganic materials, enabling the creation of genetically and environmentally tuneable structures. The SiOx nanofibers produced through this method have potential applications in various fields, including water purification, biosensors, catalytic support, and insulation.