ABSTRACT Growing environmental concerns associated with synthetic materials have intensified the demand for sustainable alternatives derived from renewable sources. In addition, the increasing global population has led to a surge in the demand for food products including juice, resulting in the generation of substantial quantities of byproducts, which are organic waste with the potential for valorization. This study investigated the bioconversion of carrot pomace (CP), waste generated in the juice industry, into fungal biomass to produce mycelium‐based foams. Filamentous fungus (Aspergillus oryzae) was cultivated on carrot pomace through a submerged process in a bubble column bioreactor. The analysis of the scanning electron microscopy (SEM) confirmed the presence of the fungal mycelium and CP residues in the material recovered from the bioreactor. This material was mixed with water, and the suspension was subjected to different grinding cycles in an ultrafine grinder, and mycelium‐based foams were then formed via freeze‐molding and freeze‐drying. The resulting foams exhibited an average density of 21.1 kg/m3, with compressive resistance values of 5.8 kPa at 10% deformation and 20.5 kPa at 30% deformation. These mechanical properties are comparable to those of commercial lightweight foams, as indicated by the Ashby material plot. These findings demonstrate the potential of mycelium‐based foams as an alternative to synthetic materials, contributing to waste valorization and development of environmentally friendly materials.

ABSTRACT Co‐culturing fungi offers a promising strategy for generating hybrid fungal biomass with structural and functional properties for developing fungal‐based alternative leather. In this study, two filamentous fungi, Aspergillus oryzae and Rhizopus delemar, were co‐cultured to valorise food waste through production of fungal materials with enhanced mechanical properties owing to chitin‐rich biomass of A. oryzae and chitin‐chitosan‐rich biomass of R. delemar. After confirming symbiotic growth on solid media and in submerged semi‐synthetic media, the system was applied to a complex medium prepared from bread and lemon waste. Cultivation was scaled up to a 4.5 L bubble‐column bioreactor. The harvested biomass was tanned with chestnut tannin and processed into materials using wet‐laid method. Symbiotic growth was verified by polymerase chain reaction (PCR) amplification and visually via optical and scanning electron microscopy (SEM). Unlike the pelletised morphology typical of A. oryzae, the co‐culture produced dispersed mycelium favouring material formation. Co‐cultures yielded higher ethanol concentrations (12–14 g/L), with biomass yields exceeding those of R. delemar (~0.2 g/g) and comparable to A. oryzae (~0.3 g/g) monocultures. The highest tensile strength and elongation achieved were 11.7 MPa and 8% respectively. Overall, this work establishes fungal‐fungal co‐culture as a transformative approach for producing hybrid biomass for fungal‐based leather alternatives.

Stereolithography (SLA) and digital light processing (DLP) are rapidly expanding UV-curing additive manufacturing (AM) technologies, recognized for their high resolution and processing speed. In parallel, itaconic acid-based resins have emerged as promising UV-curable formulations, offering high renewable content, compatibility with established diluents, and structural versatility through facile molecular modification. Despite these advantages, the end-of-life strategies remain insufficiently investigated, hindering integration into sustainable manufacturing frameworks. Here, we present 3D-printable disulfide-based covalent adaptable networks (CANs) derived from itaconic acid. The synthesized unsaturated polyester resins were readily formulated with multiple commercial diluents. The resulting systems were evaluated with respect to printability and thermomechanical performance, resulting in 3D printed materials with a glass transition temperature range between 53 and 76 degrees C and elongation at break between 93 and 142%. The recyclability of the manufactured parts was evaluated through three consecutive cycles of thermal reprocessing or grinding to be utilized as component in new resin formulations. Our findings highlight the potential of disulfide-containing itaconate networks as a versatile platform for next-generation light processable AM resins.

Mycelium-based materials are promising environmentally friendly alternatives to synthetic materials. Utilizing industrial fruit and vegetable waste as a low-cost substrate presents a potential pathway for large-scale fungal biomass (FB) production, thereby facilitating the production of mycelium-based materials. In this study, carrot pomace (CP) was used as a substrate for cultivating two filamentous fungi, Rhizopus delemar and Aspergillus oryzae (AO), in bench-scale bioreactors. Harvested solids containing mycelium and CP residues were processed into hybrid paper, mycelium-based paper (MBP), through a wet-laid process. To obtain flexible paper, MBP was then post-treated with glycerol as a plasticizer. Scanning electron microscopy images of the recovered solids showed an interconnected thin microfibrillar structure in AO, whereas Rhizopus delemar demonstrated shorter microfibers with larger diameters. The cross-sectional images of AO-MBP showed a more entangled network structure, with a smaller average pore size (36 μm) compared to RD-MBP (45.7 μm), indicating a more compact microstructure. The tensile strength of AO-MBP was 49 MPa, while RD-MBP displayed a lower tensile strength of 32 MPa. Post-treatment with glycerol reduced average pore size and tensile strength; however, elongation at break was enhanced by 60% for both AO-MBP and RD-MBP compared to untreated samples, resulting in a flexible material suitable for use as wrapping paper. The mechanical properties of MBP were comparable to those of commercial paper products, according to the material property charts. This paves the way for a fungal biorefinery concept for valorizing CP to novel paper-like products with potential applications in packaging.

Protein extraction from wheat bran is challenging due to its multi-layer and fiber-rich structure. Here, opening aleurone cells, via dry and wet milling, their combination and a novel ultrafine milling, and its effect on wheat bran's protein recovery using the alkaline solubilization/isoelectric precipitation and protein structure, functionality, and phytate content were investigated. Wet milling and ultrafine milling improved protein recovery and purity but only ultrafine milling reduced bran particle size to the aleurone cells and exposed their structure. Despite this, ultrafine milling did not significantly increase protein yield compared to wet milling, which partially opened the aleurone cells, meaning that opening the cells per se is not enough for extracting their protein. Proteins extracted with the aid of ultrafine milling had smaller particle sizes with significantly better water solubility (>2-fold) and rheological properties. Both wet milling and ultrafine milling significantly improved the removal of phytate during the wet fractionation process. Altogether, optimizing milling techniques offers a promising path to enhance accessibility to wheat bran proteins and their quality if carefully fine-tuned but other assistant technologies are necessary for boosting the recovery of the released protein from aleurone cells.

Despite being considered a premium material, leather poses both environmental and ethical issues. Thus, sustainable alternatives such as vegan leather are in high demand. Therefore, in this study, we aimed to produce vegan leather using vegetable tannins and fungi grown on bread waste. Fungal cultivation was carried out in a bubble column bioreactor using nutrients extracted from bread as substrate. To obtain tanned biomass, the biomass was subjected to vegetable tanning (using Tara, Myrobalan, Chestnut, and Indusol ATO tannins). A mild alkali treatment isolated the fibrous cell wall material from fungal biomass. Different composite sheets were prepared by wet-laying the tanned biomass and cell wall material and placing them in a multilayer arrangement. The composites were post-treated with glycerol and a bio-based binder to improve their mechanical properties. Myrobalan-tanned biomass composites after glycerol and bio-based binder post-treatments had the highest flexibility of 14.8% elongation at break, and Tara-tanned biomass composites had the highest tensile strength of 20.5 MPa. Ashby’s chart demonstrates the relationship between the sheets produced and natural leather. SEM was used to demonstrate the softer and smoother morphologies of the Chestnut and Indusol ATO-tanned composite sheets after post-treatment. Overall, this study presents multilayer fungal biocomposites as a promising vegan alternative leather.

Food-waste-derived bio-based materials offer both environmental and economic advantages. We utilised waste lemon peel as substrate to generate value-added materials from chitosan-rich fungal cell wall of Rhizopus delemar and purified cellulose from pre-treated solid residues. Nutrient from lemon peel was used for fungal cultivation and the cell wall was isolated from the obtained fungal biomass using mild alkali treatment. The fungal cell wall was used to develop a hydrogel through protonation of amino groups in chitosan by lactic acid addition. This hydrogel served as spinning dope to produce fungal monofilaments using dry gel spinning with a tensile strength of 85 MPa. Simultaneously, cellulose purified from pre-treated solid residues, converted to micro-nanocellulose suspension via mechanical fibrillation and underwent dry gel spinning to produce cellulose monofilaments with a tensile strength of 298 MPa. Cellulose fraction was analysed using XRD, FTIR, TGA, and elemental analyses. The micro- and nanoscale structures of fibrillated cellulose were verified by SEM and AFM. The findings of this study demonstrate a novel holistic valorisation approach for lemon peel waste as a resource for bio-based monofilaments, which could be used as alternatives to commercial fibres in textiles.

Citrus waste has been used as a source of bioplastics for research in different ways. Because the juice industry produces significant amounts of residue each year, it would be advantageous to use the byproducts in the creation of new materials. Researchers have long explored eco-friendly methods to convert citrus and other organic waste into polymers for producing biodegradable films. The goal of this study is to create biofilms from orange waste (OW) and ginger waste (GW) using an ultrafine grinder and study the films’ properties. Since pectin has the ability to gel, and because cellulosic fibers are strong, citrus waste has been studied for its potential to produce biofilms. After being washed, dried, and milled, orange and ginger waste was shaped into films using a casting process. Tensile testing was used to determine the mechanical properties of biofilms, while dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to determine their thermal properties. As the number of grinding cycles increased, the suspension’s viscosity increased from 29 mPa.s to 57 mPa.s for OW and from 217 mPa.s to 376 mPa.s for GW, while the particle size in the suspension significantly decreased. For OW and GW films, the highest tensile strength was 17 MPa and 15 MPa, respectively. The maximum strain obtained among all films was 4.8%. All the tested films were stable up to 150 °C, and maximum degradation occured after 300 °C.

Fungal mycelium is emerging as a source for sustainable bio-based materials. Fungal biomass of Aspergillus oryzae was prepared by cultivation on bread waste hydrolysate to valorize this abundant food waste. Chitin-glucan-rich alkali-insoluble material (AIM) was isolated from fungal biomass, formed into hydrogels, and wet spun into monofilaments. AIM in the form of fungal microfibers containing 0.09 g polymer of glucosamine (GlcN)/g AIM was subjected to freeze-thaw and deacetylation treatments to increase the amount of GlcN. The GlcN fraction was 0.19 and 0.34 g polymer of GlcN/g AIM, for AIM subjected to deacetylation (AIM-DAC) and freeze-thaw cycles and deacetylation (AIM-FRTH-DAC), respectively. The increased GlcN fraction enabled the formation of hydrogels via the protonation of amino groups after the addition of lactic acid. Morphological differences in the hydrogels included aggregation of the fungal microfibers in the AIM-DAC hydrogel, whereas the microfibers in the AIM-FRTH-DAC hydrogel had a porous and interconnected network. Rheological assessment revealed shear thinning behavior and gel properties of the produced hydrogels. Wet spinning of the hydrogels resulted in monofilaments with tensile strengths of up to 70 MPa and 12 % elongation at break. This demonstrates promising avenues for biomaterial development from fungal cell walls containing chitin-glucan via food waste valorization.

The current study aimed at the valorization of bread waste in a fungal biorefinery for the recovery of protein hydrolysate for food applications and monofilaments for medical textile applications. Rhizopus delemar was cultivated on bread waste in a 1 m3 airlift bioreactor to obtain fungal biomass. The protein hydrolysate was isolated as a soluble fraction after a mild enzymatic treatment of fungal biomass with a protease enzyme. The recovered protein hydrolysate was rich in eight essential amino acids and showed foaming and emulsion properties. The fungal microfibers rich in chitin and chitosan were recovered as an insoluble fraction of fungal biomass during the protease treatment process. A hydrogel of the fungal microfibers was wet-spun to monofilaments, which showed high elongation at break. In in vitro scratch assay, the monofilaments demonstrated significant improvements of the rate of cell migration and wound closure compared to viscose fibers (which are commonly used in wound healing dressings). Furthermore, fungal biomaterials in the form of microfibers, hydrogel, and monofilaments showed excellent biocompatibility against fibroblast cells and significantly enhanced cell growth at higher concentrations (above 500 μg/mL). This work suggests a sustainable approach to using abundant food wastes to create value-added products for food and medical textile applications.

The Current study aimed at valorizing carrot pomace (CP), an abundant waste from the juice industry. A water-soluble fraction of CP was separated from solid fraction of CP (SFCP) and employed as feedstock for producing fungal biomass (FB) in bench-scale bioreactors. FB combined with SFCP were used to develop mycelium-based papers (MBP) using the wet-laid method. The potential and capacity of FB, SFCP and MBP to remove dye (methylene blue) from wastewater was then investigated. The maximum achieved dye removal was 92% when using a mixture of SFCP and FB in their suspended forms. The MBP with the lowest density (549 kg/m3) reached 83% dye elimination. The findings of this study support the valorization of carrot pomace, through environmentally benign processes, to mycelium-based papers with potential application in wastewater treatment.

Abstract Background Renewable materials made using environmentally friendly processes are in high demand as a solution to reduce the pollution created by the fashion industry. In recent years, there has been a growing trend in research on renewable materials focused on bio-based materials derived from fungi. Results Recently, fungal cell wall material of a chitosan producing fungus has been wet spun to monofilaments. This paper presents a modification for the fungal monofilament spinning process, by the development of a benign method, dry gel spinning, to produce continuous monofilaments and twisted multifilament yarns, from fungal cell wall, that can be used in textile applications. The fungal biomass of Rhizopus delemar, grown using bread waste as a substrate, was subjected to alkali treatment with a dilute sodium hydroxide solution to isolate alkali-insoluble material (AIM), which mainly consists of the fungal cell wall. The treatment of AIM with dilute lactic acid resulted in hydrogel formation. The morphology of the hydrogels was pH dependent, and they exhibited shear thinning viscoelastic behavior. Dry gel spinning of the fungal hydrogels was first conducted using a simple lab-scale syringe pump to inject the hydrogels through a needle to form a monofilament, which was directly placed on a rotating receiver and left to dry at room temperature. The resulting monofilament was used to make twisted multifilament yarns. The process was then improved by incorporating a heated chamber for the quicker drying of the monofilaments (at 30⁰C). Finally, the spinning process was scaled up using a twin-screw microcompounder instead of the syringe pump. The monofilaments were several meters long and reached a tensile strength of 63 MPa with a % elongation at break of 14. When spinning was performed in the heated chamber, the tensile strength increased to 80 MPa and further increased to 103 MPa when a micro-compounder was used for spinning. Conclusion The developed dry gel spinning method shows promising results in scalability and demonstrates the potential for renewable material production using fungi. This novel approach produces materials with mechanical properties comparable to those of conventional textile fibers.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biobased and biodegradable polymer. This polymer is considered promising, but it is also rather expensive. The objective of this study was to compound PHBV with three different organic fillers considered waste: human hair waste (HHW), sawdust (SD) and chitin from shrimp shells. Thus, the cost of the biopolymer is reduced, and, at the same time, waste materials are valorised into something useful. The composites prepared were characterised by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile strength and scanning electron micrograph (SEM). Tests showed that chitin and HHW did not have a reinforcing effect on tensile strength while the SD increased the tensile strength at break to a certain degree. The biodegradation of the different composites was evaluated by a soil burial test for five months. The gravimetric test showed that neat PHBV was moderately degraded (about 5% weight loss) while reinforcing the polymer with organic waste clearly improved the biodegradation. The strongest biodegradation was achieved when the biopolymer was compounded with HHW (35% weight loss). The strong biodegradation of HHW was further demonstrated by characterisation by Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR). Characterisation by SEM showed that the surfaces of the biodegraded samples were eroded.

Carrot pomace (CP) which is generated in a large volume in the juice production process, is rich in cellulose, hemicellulose, sugars, pectin, and minerals. However, in many previous investigations, only cellulose was purified and utilized while other components of CP were discarded as waste. Here, CP was valorized into fungal biomass and cellulose with the aim of utilizing all the CP components. Enzymatic pretreatments were applied to solubilize the digestible fraction of CP including hemicellulose, pectin, sucrose, and other sugars for fungal cultivation, while cellulose remained intact in the solid fraction. The dissolved fraction was utilized as a substrate for the cultivation of an edible fungus (Rhizopus delemar). Fungal cultivation was performed in shake flasks and bench-scale bioreactors. The highest fungal biomass concentration was obtained after pretreatment with invertase (5.01 g/L) after 72 h of cultivation (36 and 42% higher than the concentrations obtained after hemicellulase and pectinase treatments, respectively). Invertase pretreatment resulted in the hydrolysis of sucrose, which could then be taken up by the fungus. Carbohydrate analysis showed 28–33% glucan, 4.1–4.9% other polysaccharides, 0.01% lignin, and 2.7–7% ash in the CP residues after enzymatic pretreatment. Fourier transform infrared spectroscopy and thermogravimetric analysis also confirmed the presence of cellulose in this fraction. The obtained fungal biomass has a high potential for food or feed applications, or as a raw material for the development of biomaterials. Cellulose could be purified from the solid fraction and used for applications such as biobased-textiles or membranes for wastewater treatment, where pure cellulose is needed.

Besides traditional application of fungi as a source of proteins for food and feed applications, recently their application as a source of biopolymers, namely polysaccharides (PSs), has got increasing attentions. Fungi are fast growing microorganisms that can recycle the nutrients from the low cost/low value waste materials and side streams and convert them to value added biopolymers. Fungal cell wall, that play important roles in the growth and survival of these microorganisms, is composed of fibrous PSs, such as chitin and glucans, as well as cementing biopolymer such as chitosan, proteins, lipids, and polyuronids, among others. Together these biopolymers create a unique dynamic structure which gives plasticity and strength to the fungal cells during their life. At the same time, it opens up opportunities for development of several biomaterials and bio-based products. This chapter discuss the state of the art regarding structure of fungal biopolymers, as well as their production, purification, and potential applications, as bioemulsifiers, biosurfactants, antimicrobial agent, wound healing material, sustainable textiles, and construction materials.

Abstract A fungal biorefinery is presented to valorize food waste to fungal monofilaments with tunable properties for different textile applications. Rhizopus delemar is successfully grown on bread waste and the fibrous cell wall is isolated. A spinnable hydrogel is produced from cell wall by protonation of amino groups of chitosan followed by homogenization and concentration. Fungal hydrogel is wet spun to form fungal monofilaments which underwent post‐treatments to tune the properties. The highest tensile strength of untreated monofilaments is 65 MPa (and 4% elongation at break). The overall highest tensile strength of 140.9 MPa, is achieved by water post‐treatment. Moreover, post‐treatment with 3% glycerol resulted in the highest elongation % at break, i.e., 14%. The uniformity of the monofilaments also increased after the post‐treatments. The obtained monofilaments are compared with commercial fibers using Ashby's plots and potential applications are discussed. The wet spun monofilaments are located in the category of natural fibers in Ashby's plots. After water and glycerol treatments, the properties shifted toward metals and elastomers, respectively. The compatibility of the monofilaments with human skin cells is supported by a biocompatibility assay. These findings demonstrate fungal monofilaments with tunable properties fitting a wide range of sustainable textiles applications.

Bio-based textiles are an emerging area of cross-disciplinary research, involving material science and design and contributing to textile sustainability. An example of a bio-based textile is an orange-waste film, which is plant-based and biodegradable and possesses mechanical properties which are comparable to some commodity plastics. The research project presented in this article aimed to explore orange-waste film as a new material for textile and fashion design and highlights how experimental co-design processes and innovation involving orange waste film as a textile material adds a new layer of material understanding to both textile design and technology-driven material research. Material-development methods were used to develop the orange-waste film, as were textile design methods with a focus on surface design. The results show that material variables such as tensile strength and elongation are dependent on the grinding process and drying temperature used for the raw material, as these determined the quality and durability of the orange-waste film and its applicability to the field of textile design. The use of orange waste in the creation of textiles opens up for more ways of thinking about and working with materials, and orange waste could become a desirable raw material for textile design on the basis that it introduces certain aesthetic and functional possibilities through its visual and tactile expression and material behaviour, in addition to defining methods of producing textiles.

The fungus Rhizopus delemar was grown on bread waste in a submerged cultivation process and wet-laid into films. Alkali or enzyme treatments were used to isolate the fungal cell wall. A heat treatment was also applied to deactivate biological activity of the fungus. Homogenization of fungal biomass was done by an iterative ultrafine grinding process. Finally, the biomass was cast into films by a wet-laid process. Ultrafine grinding resulted in densification of the films. Fungal films showed tensile strengths of up to 18.1 MPa, a Young’s modulus of 2.3 GPa and a strain at break of 1.4%. Highest tensile strength was achieved using alkali treatment, with SEM analysis showing a dense and highly organized structure. In contrast, less organized structures were obtained using enzymatic or heat treatments. A cell viability assay and fluorescent staining confirmed the biocompatibility of the films. A promising route for food waste valorization to sustainable fungal wet-laid films was established.

Here, cell wall of a zygomycete fungus, Rhizopus delemar, grown on bread waste was wet spun into monofilaments. Using the whole cell wall material omits the common chitosan isolation and purification steps and leads to higher material utilization. The fungal cell wall contained 36.9% and 19.7% chitosan and chitin, respectively. Solid state NMR of the fungal cell wall material confirmed the presence of chitosan, chitin, and other carbohydrates. Hydrogels were prepared by ultrafine grinding of the cell wall, followed by addition of lactic acid to protonate the amino groups of chitosan, and subsequently wet spun into monofilaments. The monofilament inhibited the growth of Bacillus megaterium (Gram+ bacterium) and Escherichia coli (Gram- bacterium) significantly (92.2% and 99.7% respectively). Cytotoxicity was evaluated using an in vitro assay with human dermal fibroblasts, indicating no toxic inducement from exposure of the monofilaments. The antimicrobial and biocompatible fungal monofilaments, open new avenues for sustainable biomedical textiles from abundant food waste.

Food waste and fashion pollution are two of the most prominent global environmental issues. To alleviate the problems associated with food waste, while simultaneously contributing to sustainable fashion, the feasibility of making an alternative textile material with leather-like properties from fungal biomass cultivated on bread waste was investigated. The filamentous fungus, Rhizopus delemar, was successfully grown on waste bread in a submerged cultivation process, and fungal biomass was treated with vegetable tannin of chestnut wood. NMR and FTIR confirmed interactions between tannin and fungal biomass, while OM, SEM and AFM visualised the changes in the hyphae upon the tannin treatment. Thermal stability was assessed using TGA analysis. The wet-laid technique commonly utilised for paper-making was used to prepare sheets of hyphae. Some of the sheets were treated with glycerol and/or a biobased binder as post-treatment. Overall, three of the produced materials exhibited leather-like properties comparable to that of natural leather. Sheets from untreated biomass with only glycerol post-treatment showed a tensile strength of 7.7 MPa and an elongation at break of 5%. Whereas sheets from untreated biomass and tannin treated biomass with both glycerol and binder treatments led to tensile strengths of 7.1 MPa and 6.9 MPa, and the elongation at break of 12% and 17%, respectively. The enhancement of hydrophobicity after the binder treatment, helped to preserve the absorbed glycerol within the sheet and thereby the flexibility was retained when in contact with moisture. These findings demonstrate that bread waste-derived fungal sheets have great potential as environmentally friendly materials with leather-like properties.