Advanced Materials From Fungal Mycelium: Fabrication and Tuning of Physical Properties

Radiation protection and structural stability of fungal melanin polylactic acid biocomposites in low Earth orbit

Materials in low Earth orbit (LEO) face radiation, atomic oxygen erosion, and extreme temperature fluctuations, which can severely compromise their structural and functional integrity. Developing lightweight, multifunctional materials capable of withstanding these harsh conditions is critical for long-term space exploration and sustainable extraterrestrial settlements. This study evaluates the structural stability and radiation shielding efficacy of polylactic acid (PLA) and biocomposites, including PLA infused with fungal melanin, synthetic melanin, or animal melanin, and a compressed mycelium (CMy) coated with PLA (PLA-CMy), after exposure to the LEO environment. Samples were deployed on the Materials International Space Station Experiment-Flight Facility platform for approximately 6 mo in zenith- and wake-facing orientations. Postflight analyses comparing flight-exposed samples to Earth controls revealed composition- and orientation-dependent differences in mass loss, optical properties, and surface morphology. Notably, fungal melanin reduced mass loss and surface wrinkle formation, indicating a protective effect against PLA degradation in LEO. Biocomposites also demonstrated shielding effects by protecting an underlying polyvinyl chloride backing layer from damage. These findings demonstrate PLA's performance in space and highlight fungal melanin as a bioderived additive to enhance PLA resilience under LEO conditions, advancing the development of sustainable materials for future space missions.

Multilayer biocomposite vegan leather materials derived from vegetable-tanned fungal biomass cultivated on food waste

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.

Subcritical water extraction improves the ability of Auricularia cornea var. Li. Polysaccharides to stabilize hydrogels and emulsion gels

In this work, polysaccharides from Auricularia cornea var. Li. (ACP) were extracted by a novel subcritical water extraction (SWE) method. Their structural properties and ability to stabilize hydrogels and emulsion gels were investigated and compared with those obtained by the conventional hot water extraction (HWE) method. The results showed that the polysaccharide yield of SWE (45.11 ± 0.23 %) was higher than that of HWE (17.85 ± 0.51 %). The two polysaccharides had the same type of monosaccharides but different compositions, and the molecular weight of ACP-SWE was slightly lower. The molecular conformation of ACP-HWE exhibited a long-chain structure, whereas ACP-SWE was multi-branched with obvious entanglements between the molecular chains. Both polysaccharides were able to form gels at concentrations above 1.0 %, with the ACP-SWE hydrogel having a denser network structure with better rheological and textural properties. ACP-SWE also had a greater ability to stabilize emulsion gels. By adjusting the polysaccharide concentration (c, 0.2 %-1.0 %) and the oil phase volume fraction (φ, 0.4-0.8), ACP-SWE emulsion gels could be prepared in a single step of shear homogenization. This work revealed that the adsorption of ACP-SWE at the oil-water interface and cross-linking in the bulk phase, together with the filling effect of oil droplets, contributed to the stabilization of ACP-SWE emulsion gels.

Pure mycelium materials production from agri-processing water: Effects of feedstock composition on material properties for packaging applications

In this work, pure mycelium materials (PMMs) were produced by cultivating fungi Trametes versicolor and Irpex lacteus on lignocellulose-rich agricultural processing water. This water was a side stream from the alkali treatment of purposely grown biomass (miscanthus) for cellulose fiber extraction and contained lignocellulosic residues. Agri-processing water yielded ~75-mg/L PMMs with superior mechano-physical properties than synthetic medium-based ones. These properties were further enhanced by PMM post-processing with glycerol. The thermal stability of PMMs was demonstrated by their higher melting temperature than low density polyethylene (LDPE) while their degradation between 200-380°C, and density of <1.0 g/cm3, like LDPE. Their mechanical performance was studied on filmlike specimens via dynamic mechanical analyzer. PMMs showed a viscoelastic behavior with a high storage modulus of 34 MPa at 65°C suggesting their suitability for packaging applications. This work provides guidelines on optimizing PMM production using agri-processing water to obtain tunable mechano-physical properties. PRACTITIONER POINTS: Valorization of agri-processing water to produce high-value PMM packaging products. No pure or expensive nutrient supplementation was needed for agri-based feedstock. Relationships between feedstock composition and PMM properties were established. PMMs showed a similar thermal profile and density as typical petro-based packaging materials. The addition of glycerol postproduction induced flexibility in PMMs.

Generalizable Metamaterials Design Techniques Inspire Efficient Mycelial Materials Inverse Design

Fungal mycelial materials can mimic numerous nonrenewable materials; they are even capable of outperforming certain materials at their own applications. Fungi's versatility makes mock leather, bricks, wood, foam, meats, and many other products possible. That said, there is currently a critical need to develop efficient mycelial materials design techniques. In mycelial materials, and the wider field of biomaterials, design is primarily limited to costly forward techniques. New mycelial materials could be developed faster and cheaper with robust inverse design techniques, which are not currently used within the field. However, computational inverse design techniques will not be tractable unless clear and concrete design parameters are defined for fungi, derived from genotype and bulk phenotype characteristics. Through mycelial materials case studies and a comprehensive review of metamaterials design techniques, we identify three critical needs that must be addressed to implement computational inverse design in mycelial materials. These critical needs are the following: 1) heuristic search/optimization algorithms, 2) efficient mathematical modeling, and 3) dimensionality reduction techniques. Metamaterials researchers already use many of these computational techniques that can be adapted for mycelial materials inverse design. Then, we suggest mycelium-specific parameters as well as how to measure and use them. Ultimately, based on a review of metamaterials research and the current state of mycelial materials design, we synthesize a generalizable inverse design paradigm that can be applied to mycelial materials or related design fields.

The future potential of controlled environment agriculture

The production of high-quality food needs to increase to feed the growing global population. Controlled environment agriculture (CEA) systems in a vertical farm setting-in which several layers are stacked above each other, thus increasing the area for growth-can substantially boost productivity for crops, algae, mushrooms, fish, insects, and cultured meat. These systems are independent of climate, weather, and region, offering reduced environmental impact, although they come with high energy demands. An easy-to-understand, quantitative performance assessment of the theoretical potential for these 6 CEA systems is proposed here. It compares them against the world's main food production system: field production of maize, wheat, rice, and soybean. CEA could play a pivotal role in the global food supply if efficiencies in energy, control of growth environments, and waste stream utilization are vastly improved. Technological advancements, targeted policy support and public engagement strategies will be necessary to significantly reduce production costs and increase public acceptance.

The prospect of mushroom as an alterative protein: From acquisition routes to nutritional quality, biological activity, application and beyond

There is a need for new protein sources to sustainably feed the world. Mushroom proteins are regarded as a future protein alternative considering their low cost, high nutritional quality, and excellent digestibility, have attracted increasing attention. Proteins with multiple structural characteristics endow mushroom with various bioactivities, which has also broadened application of mushroom in nutrition, food fields, as well as in emerging industries. Therefore, the present review narrates the recent developments in nutritional quality of mushroom proteins, while paying considerable attention to cultivation technologies and preparation strategies of mushroom proteins. Moreover, the types, properties and biological benefits of mushroom proteins were summarized, herein the latest research on applications of mushroom or their proteins was highlighted. Eventually, the challenges confronting their widespread utility, despite their high nutritional content were discussed. This review would provide a new appreciation for the future use of mushroom proteins.

The Influences of Different Mixing Methods for Fungi and Substrates on the Mechanical and Physicochemical Properties of Mycelium Composites

At present, the research on mycelium composites mainly focuses on the optimization of the preparation process, while the initial culture stage of the mixing method of fungi and substrates is often overlooked. This study is centered on exploring the impacts of different mixing methods on the appearance, mechanical properties, water absorption, and chemical and thermal decomposition characteristics of mycelium composites, aiming to identify a suitable mixing method. The experimental results show that different methods lead to significant differences in the mechanical properties of the materials. The compressive strength of the fungal inoculation group and the pre-culture group is ≥0.08 MPa, and the flexural strength is ≥11 N. The electron microscope results also confirm the effects of mycelium content and the interaction between mycelium and the matrix on the mechanical properties. The change range of the water absorption rate of the materials begins to increase at 30-60 min of immersion. After 60 min of immersion, the order of the water absorption rate is pre-culture < fungal inoculation < secondary inoculation. The mycelium membrane on the surface of the materials is beneficial for water resistance. The materials prepared by different methods have volume losses and similar thermal distributions, starting to degrade at approximately 170 °C and reaching maximum degradation at 350 °C. This study provides a reference for the optimization of the preparation of mycelium composites.

Bioplastics and biodegradable plastics: A review of recent advances, feasibility and cleaner production

As awareness of plastic pollution increases, there is a growing emphasis on sustainable alternatives. Bioplastics and biodegradable plastics have surfaced as potential substitutes. Yet, their limited properties and high production costs hinder their practicality. This paper systematically reviews more than 280 articles to comprehensively outline the advantages and drawbacks of emerging bioplastics and biodegradable plastics, alongside advancements in cleaner production methods. Bioplastics, sourced from renewable materials, decrease dependency on fossil fuels and help lower carbon footprints during production and disposal. Some bioplastics, such as polylactic acid (PLA) and polyhydroxyalkanoates, are compostable, but their manufacturing costs usually surpass that of conventional plastics. Additionally, certain bioplastics exhibit lower mechanical strength, heat resistance, or durability. PLA and bio-polybutylene succinate (bio-PBS) are viable for single-use items and biodegradable products, with scalable production using established technologies, although bio-PBS is somewhat pricier than PLA. Biodegradable plastics lessen environmental impact by naturally degrading and can be composted in industrial settings, providing an eco-friendly disposal option. However, they require specific industrial composting conditions for complete degradation, which can lead to microplastic formation in the environment. PBS, polybutylene adipate terephthalate, and polybutylene succinate-co-adipate seem to be the most promising options, with PBS being a strong contender for replacing traditional plastics due to its biodegradable and compostable nature. It has the potential to be partially or entirely bio-based (bio-PBS). Innovative technologies, especially next-generation industrial biotechnology and microbial cell factories, offer cleaner methods for synthesizing these plastics. This review aids in identifying feasible and sustainable alternatives to conventional plastics.

Experimental Assessment of Multiple Properties of Mycelium-Based Composites with Sewage Sludge and Bagasse

Mycelium-based composites (MBCs) have a lot of potential as an alternative lightweight material due to their small environmental footprint and their biodegradability. The unique properties of cellulose-rich sewage sludge (SS) allow it to be used as a substrate for manufacturing MBCs. In order to examine the feasibility of creating MBCs using SS, this study used SS and bagasse as nutrient substrates and cultivated MBCs on ready-made mycelium (Pleurotus ostreatus). The physico-mechanical properties, morphological properties, and thermal stability of MBCs were tested and analyzed. The results show that both the bagasse and SS promoted fungal growth to create a dense mycelial network on day 10. Adding SS increased the density and compressive strength. The volume shrinkage of the MBCs first decreased and then increased. The optimal ratio of ready-made mycelium-sewage sludge was 2:1. The thermal conductivity of the bagasse-based MBCs was 0.12 Wm-1K-1 and that of the SS-based MBCs was 0.13 Wm-1K-1. These physico-mechanical characteristics satisfy the requirements of lightweight backfill materials for use in highways. Additionally, the SS supported more robust growth of hyphae and resulted in stronger MBCs. In comparison to bagasse, it also showed better thermal stability and a higher residual mass. It is feasible to produce MBCs with SS, and the biocomposite proposed in this study could be used as a lightweight backfill material of the type that is widely needed for use in highway construction and maintenance.

Characterization of plant growth-promoting endophytic fungi from Aegle marmelos Corr. and their role in growth enhancement and yield in rice

Plant growth-promoting endophytes (PGPE) are microorganisms which reside in plant tissues and are beneficial to the host in plant growth promotion and pathogen resistance. They are the eco-friendly and sustainable alternative to chemical fertilizers and pesticides. This study aimed to analyze the plant growth-promoting properties of the five endophytic fungal strains from the medicinal plant Aegle marmelos Corr. and evaluate their effects on Oryza sativa plants. Firstly, endophytes were isolated from the different parts of A. marmelos and identified by ITS sequencing. Phosphate solubilization ability was checked in Pikovskaya's agar medium, IAA secretion was measured by the Salkowski colourimetric method, and ACC deaminase activity was checked by Penrose's method. Four endophytic fungal strains with promising PGP activities were inoculated into rice seeds to check their growth promotion in rice. The strain Purpureocillium lilacinum (AMR2) enhanced the seed vigour of rice seeds and demonstrated excellent root colonization ability. Periconia byssoides (AML2) and Medicopsis romeroi (AMS3) were the most effective plant growth-promoting agents, leading to both crop yield improvement and enhanced plant morphological growth due to their great ability to solubilize inorganic phosphate, ACC deaminase activity and production of IAA and Gibberellin A3 (GA3). These endophytic strains could serve as microbial inoculants to enhance crop production, offering an eco-friendly alternative.

Mycelium-based composites: An updated comprehensive overview

Mycelium-based composites hold significant potential as sustainable alternatives to traditional materials, offering innovative solutions to the escalating challenges of global warming and climate change. This review examines their production techniques, advantages, and limitations, emphasizing their role in addressing pressing environmental and economic concerns. Current applications span various industries, including manufacturing and biomedical fields, where mycelium-based composites demonstrate the capacity to mitigate environmental impact and enhance economic sustainability. Key findings highlight their environmental benefits, economic viability, and versatile applications, showcasing their potential to revolutionize multiple sectors. However, challenges such as consumer acceptance, intrinsic variability, and the need for standardized guidelines persist, underscoring the importance of further research and innovation. By optimizing material properties and refining production processes, mycelium-based composites could pave the way for widespread adoption as sustainable materials, contributing to a greener and more environmentally conscious future.

Development and characterization of starch/polyvinyl alcohol active films with slow-release property by utilizing Mucorracemosus Fresenius mycelium to load with clove essential oil

The controlled release active packaging film represents a novel technology that always can effectively slow down the release of active agents, extending their efficacy. Mucorracemosus Fresenius (MF) mycelium was prepared and used as an adsorption carrier to load clove essential oil (CEO). The CEO/MF complexes were incorporated into the starch/polyvinyl alcohol (Starch/PVA) matrix to develop active films. The effects of MF content on the films' properties were investigated. MF exhibited the internal hollow structure with diaphragm inside and showed antioxidant activity. The adsorption rate of MF on CEO was 238.09 %. As MF increased, the tensile strength, water contact angle and gas barrier properties (water vapor and oxygen) of the films containing CEO enhanced. The release rate of CEO from the films into food simulant (10 % ethanol) slowed down significantly with increasing of MF. Compared to the film without MF, the film with highest MF delayed 33 h to reach equilibrium. The films with different content of MF showed different antioxidant and antibacterial activities, and different preservation effects on shrimp. It showed a great prospect to develop controlled release active films by utilizing MF mycelium as an adsorption material, which enriched the technical solutions for developing controlled release active packaging films.

Metabolic profiling of two white-rot fungi during 4-hydroxybenzoate conversion reveals biotechnologically relevant biosynthetic pathways

White-rot fungi are efficient organisms for the mineralization of lignin and polysaccharides into CO2 and H2O. Despite their biotechnological potential, WRF metabolism remains underexplored. Building on recent findings regarding the utilization of lignin-related aromatic compounds as carbon sources by WRF, we aimed to gain further insights into these catabolic processes. For this purpose, Trametes versicolor and Gelatoporia subvermispora were incubated in varying conditions - in static and agitation modes and different antioxidant levels - during the conversion of 4-hydroxybenzoic acid (a lignin-related compound) and cellobiose. Their metabolic responses were assessed via transcriptomics, proteomics, lipidomics, metabolomics, and microscopy analyses. These analyses reveal the significant impact of cultivation conditions on sugar and aromatic catabolic pathways, as well as lipid composition of the fungal mycelia. Additionally, this study identifies biosynthetic pathways for the production of extracellular fatty acids and phenylpropanoids - both products with relevance in biotechnological applications - and provides insights into carbon fate in nature.

Boosting photosynthesis opens new opportunities for agriculture sustainability and circular economy: The BEST-CROP research and innovation action

There is a need for ground-breaking technologies to boost crop yield, both grains and biomass, and their processing into economically competitive materials. Novel cereals with enhanced photosynthesis and assimilation of greenhouse gasses, such as carbon dioxide and ozone, and tailored straw suitable for industrial manufacturing, open a new perspective for the circular economy. Here we describe the vision, strategies, and objectives of BEST-CROP, a Horizon-Europe and United Kingdom Research and Innovation (UKRI) funded project that relies on an alliance of academic plant scientists teaming up with plant breeding companies and straw processing companies to use the major advances in photosynthetic knowledge to improve barley biomass and to exploit the variability of barley straw quality and composition. We adopt the most promising strategies to improve the photosynthetic properties and ozone assimilation capacity of barley: (i) tuning leaf chlorophyll content and modifying canopy architecture; (ii) increasing the kinetics of photosynthetic responses to changes in irradiance; (iii) introducing photorespiration bypasses; (iv) modulating stomatal opening, thus increasing the rate of carbon dioxide fixation and ozone assimilation. We expect that by improving our targeted traits we will achieve increases in aboveground total biomass production without modification of the harvest index, with added benefits in sustainability via better resource-use efficiency of water and nitrogen. In parallel, the resulting barley straw is tailored to: (i) increase straw protein content to make it suitable for the development of alternative biolubricants and feed sources; (ii) control cellulose/lignin contents and lignin properties to develop straw-based construction panels and polymer composites. Overall, by exploiting natural- and induced-genetic variability as well as gene editing and transgenic engineering, BEST-CROP will lead to multi-purpose next generation barley cultivars supporting sustainable agriculture and capable of straw-based applications.

A pioneering review on Ganoderma lucidum-derived leather: taking a step towards a cruelty-free leather manufacturing

Ganoderma lucidum-derived leather presents a sustainable alternative to traditional leather, addressing ethical, environmental, and socio-economic concerns in the fashion industry. This study explores the advantages of G. lucidum-derived leather, including its cruelty-free nature, eco-friendly characteristics, and positive social and economic implications. By eliminating the need for animal exploitation, G. lucidum-derived leather aligns with ethical consumer preferences and promotes compassion towards animals. Additionally, its production process is environmentally friendly, utilizing organic substrates and avoiding toxic chemicals, thereby reducing pollution and minimizing ecological footprints. Furthermore, G. lucidum-derived leather offers significant social and economic benefits, enhancing brand reputation and attracting socially conscious consumers. Its cultivation creates economic opportunities in rural communities, stimulating local economies and providing jobs in mushroom cultivation and leather manufacturing. However, challenges remain, such as the need for further research on its mechanical properties and biodegradability. G. lucidum-derived leather represents a promising solution to the challenges facing the fashion industry, offering a sustainable and ethical alternative that meets the demands of conscious consumers and promotes environmental stewardship.

Sustainable leather alternatives: High-performance and dyeable bio-based materials from fungal chitin and tannic acid

Leather alternatives (LAs) offer a promising solution to address the environmental and ethical concerns associated with traditional leather production relying animal hides and chemical tanning agents. However, synthetic polymer-based LAs, such as polyurethane and polyvinyl chloride, have limited broader applications due to their complex manufacture process, high emission of volatile organic compounds, and poor biodegradability. Herein, we present the development of biomass-based LAs fabricated by combining two low-cost natural components - fungal chitin and plant polyphenols (i.e., tannic acid, TA), through non-covalent interactions. Specifically, chitin was extracted from common mushrooms (e.g., Pleurotus ostreatus and Agaricus bisporus) through alkali treatment, and the biodegradable LAs were subsequently prepared by filtration, TA crosslinking, hot pressing, and dyeing. The incorporation of TA significantly enhanced the mechanical and antibacterial properties of LAs, achieving a tensile strength of 156 MPa. Additionally, the chitin-based LAs exhibited good water vapor permeability and were dyed in various colors with excellent levelness and fastness. Importantly, this synthetic strategy avoided the use of organic solvents and hazardous chemicals, showing potential for large-scale production. This work provides a simple and effective strategy to prepare biodegradable LAs from low-cost non-animal resources, aligning with social ethical standards and environmental requirements for sustainable development.

Review on mushroom mycelium-based products and their production process: from upstream to downstream

The global trend toward carbon neutrality and sustainability calls for collaborative efforts in both the basic and applied research sectors to utilize mushroom mycelia as environmentally friendly and sustainable materials. Fungi, along with animals and plants, are one of the major eukaryotic life forms. They have long been utilized in traditional biotechnology sectors, such as food fermentation, antibiotic production, and industrial enzyme production. Some fungi have also been consumed as major food crops, such as the fruiting bodies of various mushrooms. Recently, new trends have emerged, shifting from traditional applications towards the innovative use of mushroom mycelium as eco-friendly bioresources. This approach has gained attention in the development of alternative meats, mycofabrication of biocomposites, and production of mycelial leather and fabrics. These applications aim to replace animal husbandry and recycle agricultural waste for use in construction and electrical materials. This paper reviews current research trends on industrial applications of mushroom mycelia, covering strain improvements and molecular breeding as well as mycelial products and the production processes. Key findings, practical considerations, and valorization are also discussed.

Expression of spider silk protein in tobacco improves drought tolerance with minimal effects on its mechanotype

Spider silk, especially dragline silk from golden silk spiders (Trichonephila clavipes), is an excellent natural material with remarkable mechanical properties. Many studies have focused on the use of plants as biofactories for the production of recombinant spider silk. However, the effects of this material on the mechanical properties or physiology of transgenic plants remain poorly understood. Since glycine-rich proteins play key roles in plants, we evaluated the effects of a glycine-rich spider silk protein on plant mechanical properties (mechanotype) and physiology. We generated tobacco (Nicotiana tabacum) plants producing a nucleus- or plastid-encoded partial component of dragline silk, MaSp1 (major ampullate spidroin-1; MaSp1-tobacco), containing six repetitive glycine-rich and polyalanine tandem domains. MaSp1 accumulation had minimal effect on leaf mechanical properties, but improved drought tolerance. Transcriptome analysis of drought-stressed MaSp1-tobacco revealed the upregulation of genes involved in stress response, antioxidant activity, cellular metabolism and homeostasis, and phenylpropanoid biosynthesis. The effects of drought treatment differed between the nucleus- and the plastid-encoded MaSp1-tobacco, with the latter showing a stronger transcriptomic response and a higher total antioxidant status (TAS). Well-watered MaSp1-tobacco displayed elevated levels of the stress phytohormone ABA, leading to stomatal closure, reduced water loss, activation of stress response, and increased TAS. We show that the moderately enhanced ABA content in these plants plays a pivotal role in drought tolerance, alongside, ABA priming, which causes overall adjustments in multiple drought tolerance mechanisms. Thus, our findings highlight the potential of utilizing glycine-rich spider silk proteins to enhance plant resilience to drought.

Aspergillus nidulans cell wall integrity kinase, MpkA, impacts cellular phenotypes that alter mycelial-material mechanical properties

Mycelial materials are an emerging, natural material made from filamentous fungi that have the potential to replace unsustainable materials used in numerous commercial applications (e.g., packaging, textiles, construction). Efforts to change the mechanical properties of mycelial-materials have typically involved altering growth medium, processing approaches, or fungal species. Although these efforts have shown varying levels of success, all approaches have shown there is a strong correlation between phenotype (of both fungal mycelia and mycelial material's assembly) and resultant mechanical properties. We hypothesize that genetic means can be used to generate specific fungal phenotypes, leading to mycelial materials with specific mechanical properties. To begin to test this hypothesis, we used a mutant of the model filamentous fungus, Aspergillus nidulans, with a deletion in the gene encoding the last kinase in the cell wall integrity (CWI) signaling pathway, mpkA. We generated one set of mycelial materials from the ΔmpkA deletion mutant (A1404), and another from its isogenic parent (A1405; control). When subjected to tensile testing, and compared to material generated from the control, ΔmpkA material has similar elastic modulus, but significantly increased ultimate tensile strength, and strain at failure. When subjected to a fragmentation assay (i.e., resistance to shear-stress), the ΔmpkA material also had higher relative mechanical strength. To determine possible causes for this behavior, we carried out a comprehensive set of phenotype assessments focused on: three-dimensional structure, hyphal morphology, hyphal growth behaviors, and conidial development. We found, compared to the control, material generated from the ΔmpkA mutant manifests significantly less development, a modified cell wall composition, larger diameter hyphae, more total biomass, higher water capacity and more densely packed material, which all appear to impact the altered mechanical properties.

Tailoring the Mechanical Properties of Fungal Mycelium Mats with Material Extrusion Additive Manufacturing of PHBH and PLA Biopolymers

To advance the concept of a circular economy, fungal mycelium-based materials are drawing increased attention as substitutes for nonsustainable materials, such as petroleum-based and animal-derived products, due to their biodegradability, low carbon footprint, and cruelty-free nature. Addressing the challenge of mechanical properties in fungal mycelium products, this study presents a straightforward approach for reinforcing fungal mycelium mats. This is achieved by using two bio-based and biodegradable polymers, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) and polylactic acid (PLA), via material extrusion additive manufacturing (MEX AM), commonly known as 3D printing, to produce fungal mycelium-biopolymer composites. By analyzing the mechanical properties, roughness, and morphology, this study demonstrates significant improvements in ultimate tensile strength with the application of PHBH and even more with PLA, while elasticity is reduced. The study also discusses potential improvements to enhance the quality of the fungal mycelium-biopolymer composites without trading off bio-based and biodegradable features, offering a promising pathway for the development of more durable and sustainable fungal mycelium products.

Characterization of Mycelium Biocomposites under Simulated Weathering Conditions

Expanded polystyrene (EPS) remains a popular packaging material despite environmental concerns such as pollution, difficulty to recycle, and toxicity to wildlife. The goal of this study is to evaluate the potential of an ecofriendly alternative to traditional EPS composed of a mycelium biocomposite grown from agricultural waste. In this material, the mycelium spores are incorporated into cellulosic waste, resulting in a structurally sound biocomposite completely enveloped by mycelium fibers. One of the main criteria for shipping applications is the ability of a material to withstand extreme weather conditions. Accordingly, this study focused on evaluating a commercially available mycelium material before and after exposure to various weathering conditions, including high and low temperatures at different humidity levels. Fourier transform infrared spectroscopy (FTIR) was performed to examine any transformations in the mycelium structure and composition, whereas scanning electron microscopy (SEM) was used to reveal any changes in the morphology. Similarly, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses were conducted to evaluate the thermal behavior, whereas mechanical properties were measured by using shore hardness and Izod Impact testing. Although some irreversible changes were observed due to the exposure to high temperatures, the material exhibited good thermal stability and impact resistance. FTIR analysis demonstrated small changes in the biocomposite structure and protein rearrangement as a result of weathering, whereas SEM revealed some cracking in the cellulose substrate. A combination of low temperatures and humidity resulted in significant moisture absorption, as indicated by TGA and DSC. This in turn decreased the hardness of the fibers by nearly 2-fold; however, the impact strength of the entire biocomposite remained unchanged. Overall, these results provide important insight into the structure-property relationships of mycelium-based materials.

Assessing the Conformity of Mycelium Biocomposites for Ecological Insulation Solutions

In this study, different combinations of mycelium biocomposites (MBs) were developed using primary substrates sourced from the local agricultural, wood processing, and paper industries. The physicomechanical properties, thermal conductivity, and fire behavior were evaluated. The highest bending strength was achieved in composites containing waste fibers and birch sanding dust, with a strength competitive with that of synthetic polymers like EPS and XPS, as well as some commercial building materials. The lowest thermal conductivity was observed in hemp-based MB, with a lambda coefficient of 40 m·W·m-1·K-1, making these composites competitive with non-mycelium insulation materials, including synthetic polymers such as EPS and XPS. Additionally, MB exhibited superior fire resistance compared to various synthetic foams and composite materials. They showed lower peak heat release rates (134-243 k·W·m-2) and total smoke release (7-281 m2·m-2) than synthetic polymers, and lower total heat release (6-62 k·W·m-2) compared to certain wood composites. Overall, the mechanical and thermal properties, along with the fire performance of MB, support their potential as a sustainable alternative to petroleum-based and traditional composite materials in the building industry.

Biocomposites Based on Mould Biomass and Waste Fibres for the Production of Agrotextiles: Technology Development, Material Characterization, and Agricultural Application

This study explores the potential use of mould biomass and waste fibres for the production of agrotextiles. First, 20 mould strains were screened for efficient mycelium growth, with optimized conditions of temperature, sources of carbon and nitrogen in the medium, and type of culture (submerged or surface). A method was developed for creating a biocomposite based on the mould mycelium, reinforced with commercial bleached softwood kraft (BSK) pulp and fibre additives (cotton, hemp). The best properties, including mechanical, water permeability, and air permeability, were shown by the biocomposites containing 10-20% Cladosporium cladosporioides mycelium grown in surface or submerged cultures, milled with BSK pulp, cotton, and hemp (10-20%). The mould mycelium was refined with cellulosic fibrous material, formed, pressed, and dried, resulting in a biomaterial with good mechanical parameters, low water permeability, and high air permeability. The biocomposite was fully biodegradable in soil after 10 days in field conditions. The use of the biocomposite as a crop cover shortened the germination time and increased the percentage of germinated onion, but had no effect on parsley seeds. This study shows the potential of using mould mycelium for the production of biomaterial with good properties for applications in horticulture.

Putative APSES family transcription factor mbp1 plays an essential role in regulating cell wall synthesis in the agaricomycete Pleurotus ostreatus

The clade A APSES family transcription factors (Mbp1, Swi4, and Swi6) contribute to cell wall synthesis regulation in fungi. Herein, evolutionary relationships among these proteins were clarified by phylogenetic analysis using various ascomycetes and basidiomycetes, and then the detailed function of Mbp1 in cell wall synthesis regulation was analyzed in Pleurotus ostreatus. Our phylogenetic analysis revealed that Mbp1 and Swi6 are widely conserved among various fungi, whereas Swi4 is a protein specific for Saccharomycotina. In P. ostreatus, two putative clade A APSES family transcription factors, protein ID 83192 and 134090, were found and identified as Mbp1 and Swi6, respectively. The mbp1 gene was then disrupted through homologous recombination using P. ostreatus 20b strain (Δku80) as a host to obtain mbp1 disruption strains (Δmbp1). Disruption of mbp1 significantly decreased the growth rate and shortened aerial hyphae, suggesting that Mbp1 is involved in mycelial growth, especially aerial hyphal growth. Furthermore, thinner cell walls, decreased relative percentage of β-glucan, and downregulation of all β-glucan synthase genes were observed in Δmbp1 strains. Therefore, Mbp1 plays an essential role in β-glucan synthesis regulation in P. ostreatus. Disruption of mbp1 also impacted the expression profiles of chitin synthase genes, septum formation, and sensitivity to a chitin synthesis inhibitor, suggesting that Mbp1 also regulates chitin synthesis. In conclusion, Mbp1 is responsible for normal mycelial growth and regulates β-glucan and chitin synthesis in P. ostreatus. To the best of our knowledge, this is the first report on the detailed function of Mbp1 in cell wall synthesis regulation in fungi.

Quantification of fungal biomass in mycelium composites made from diverse biogenic side streams

Mycelium composite materials are comprised of renewable organic substrates interconnected by fungal mycelium, allowing full biodegradability after use. Due to their promising material properties, adaptability, and sustainable nature, these biomaterials are investigated intensively. However, one crucial aspect that has hardly been covered so far is the proportion of fungal biomass in the composites, which would be necessary to assess its contribution to the material characteristics. Since a complete physical separation of mycelium and substrate is not feasible, we approached this issue by isolating the fungal DNA and relating it to the mass of mycelium with the help of quantitative PCR. Overall, 20 different combinations of fungi and biogenic side streams were evaluated for their handling stability, and growth observations were related to the quantification results. Ganoderma sessile was able to form stable composites with almost all substrates, and a positive correlation between mycelial biomass and composite stability could be found. However, the amount of mycelium required for fabricating firm materials strongly depends on the combination of substrate and fungal species used. Less than five mass percent of fungal biomass can suffice to achieve this, as for example when combining Trametes versicolor with sugar beet pulp, whereas a mass fraction of twenty percent leads to crumbly materials when using Pleurotus pulmonarius on green waste. These results indicate that the mycelial biomass is an important factor for the composite's stability but that the properties of the fungal hyphae, as well as those of the substrate, are also relevant. The presented quantification method not only allows to estimate fungal growth during composite production but can also improve our understanding of how the mycelium influences the material.

Perspectives of Insulating Biodegradable Composites Derived from Agricultural Lignocellulosic Biomass and Fungal Mycelium: A Comprehensive Study of Thermal Conductivity and Density Characteristics

The research suggests a production method of insulating composites created from lignocellulosic agricultural biomass with fungal mycelium as a binder agent and offers a deeper investigation of their thermophysical properties. Particularly, the samples were meticulously evaluated for density and thermal conductivity. The function was built on the suggestion by the authors regarding the thermal conductivity-weight ratio indicator. The metric was initially introduced to assess the correlation between these parameters and was also applied to qualitatively evaluate the biocomposite among other commonly used natural insulations. An applied polynomial trend analysis indicated that the most effective densities for the wheat, hemp, and flax, which were 60, 85, and 105 kg·m-3 respectively. It was determined that the optimal density for wheat and hemp composites corresponded to values of 0.28 and 0.20 W-1·kg-1·m4·K of the coefficient, respectively. These values were superior to those revealed in other common natural insulating materials, such as cork, cotton stalks, hempcrete, timber, etc. As a result, the proposed insulating material may offer numerous opportunities for application in industrial settings of civil engineering.

Sustainable production of Pleurotus sajor-caju mushrooms and biocomposites using brewer's spent and agro-industrial residues

Brazil is one of the world's largest beer producers and also a major food producer. These activities generate a large amount of residues which, if disposed of inappropriately, can have adverse effects on the environment. The objective of this research was to evaluate the potential of using these residues for both mushroom cultivation (traditional use) and the production of mycelium-based composites (innovative use). Mushroom production (Pleurotus sajor-caju) was conducted using only brewer's spent grains (fresh and dried) and also mixed with banana leaves (1:1) or peach palm leaves (1:1), which are residues widely available in the northern region of Santa Catarina, Brazil. The productivity of mushrooms cultivated using fresh and dried brewer's spent grains did not exhibit a statistically significant difference, indicating that this residue can be utilized shortly after its generation in the industrial process, thereby reducing costs associated with production. Combining brewer's spent grains with banana or peach palm leaves resulted in enhanced mushroom production (0.41 and 0.38 g day-1, respectively) compared to using the leaves as a sole substrate. The mushrooms produced contain sugars and a minimal sodium content, and are considered a source of phosphorus. In addition, no toxic elements (Hg and Pb) were present. The mycelium-based composites produced using the residual substrate (after the mushroom harvest) exhibited better mechanical properties (compressive strength = 0.04 MPa, density = 242 kg m-3, and low humidity sorption) than those produced using fresh substrate. The results demonstrate the synergistic effect of combining the two approaches under investigation. The use of brewer´s spent enhance the mushroom productivity and the residual substrate enhance the mechanical properties of mycelium-based composites. The compressive strength, density, and air humidity sorption properties are essential for determining the potential applications of mycelium-based composites. The use of brewer's spent grains mixed with banana leaves demonstrated significant promise for mushroom production and subsequent application in the development of mycelium-based composites. These sequential approaches contribute to waste valorization and the rational utilization of natural resources, as the mycelium-based composites are considered for substitution of synthetic materials, thereby promoting sustainability for future generations.

Effects of Humidity on Mycelium-Based Leather

Leather is a product that has been used for millennia. While it is a natural material, its production raises serious environmental and ethical concerns. To mitigate those, the engineering of sustainable biobased leather substitutes has become a trend over the past few years. Among the biobased materials, mycelium, the fungal "root" of a mushroom, is one of the promising alternatives to animal leather, as a material with tunable physicomechanical properties. Understanding the effect of humidity on mycelium-based leather material properties is essential to the production of durable, competitive, and sustainable leather products. To this end, we measured the water sorption isotherms on several samples of mycelium-based leather materials and investigated the effects of water sorption on their elastic properties. The ultrasonic pulse transmission method was used to measure the wave speed through the materials while measuring their sorption isotherms at different humidity levels. Additionally, the material's properties were mechanically tested by performing uniaxial tensile tests under ambient and immersed conditions. An overall reduction in elastic moduli was observed during both absorption and immersion. The changes in the measured longitudinal modulus during water sorption reveal changes in the elasticity of the test materials. The observed irreversible variation of the longitudinal modulus during the initial water sorption can be related to the material production process and the presence of various additives that affect the mechanical properties of the leather materials. Our results presented here should be of interest to material science experts developing a new generation of sustainable leather products.

Comparative Evaluation of Mechanical and Physical Properties of Mycelium Composite Boards Made from Lentinus sajor-caju with Various Ratios of Corn Husk and Sawdust

Mycelium-based composites (MBCs) exhibit varied properties as alternative biodegradable materials that can be used in various industries such as construction, furniture, household goods, and packaging. However, these properties are primarily influenced by the type of substrate used. This study aims to investigate the properties of MBCs produced from Lentinus sajor-caju strain CMU-NK0427 using different ratios of sawdust to corn husk in the development of mycelium composite boards (MCBs) with thicknesses of 8, 16, and 24 mm. The results indicate that variations in the ratios of corn husk to sawdust and thickness affected the mechanical and physical properties of the obtained MCBs. Reducing the corn husk content in the substrate increased the modulus of elasticity, density, and thermal conductivity, while increasing the corn husk content increased the bending strength, shrinkage, water absorption, and volumetric swelling. Additionally, an increase in thickness with the same substrate ratio only indicated an increase in density and shrinkage. MCBs have sound absorption properties ranging from 61 to 94% at a frequency of 1000 Hz. According to the correlation results, a reduction in corn husk content in the substrate has a significant positive effect on the reduction in bending strength, shrinkage, and water absorption in MCBs. However, a decrease in corn husk content shows a strong negative correlation with the increase in the modulus of elasticity, density, and thermal conductivity. The thickness of MCBs with the same substrate ratio only shows a significant negative correlation with the modulus of elasticity and bending strength. Compared to commercial boards, the mechanical (bending strength) and physical (density, thermal conductivity, and sound absorption) properties of MCBs made from a 100% corn husk ratio are most similar to those of softboards and acoustic boards. The results of this study can provide valuable information for the production of MCBs and will serve as a guide to enhance strategies for further improving their properties for commercial manufacturing, as well as fulfilling the long-term goal of eco-friendly recycling of lignocellulosic substrates.

Investigating the mechanism of Zn cross-linking of chitin in a mycelium-based leather substitute and its performance evaluation

Mycelium-based leather substitutes with a three-dimensional reticulated structure have attracted attention owing to the negative environmental impacts of natural and synthetic leather. This study utilised Ganoderma lucidum mycelium to prepare a mycelium-based leather substitute with zinc cross-linking (MF-Zn) and evaluated its physicochemical properties and sensory performance; the conventional Cr3+ tanning method was used as reference. Results demonstrated that Zn2+ and Cr3+ formed cross-links with the -OH and -NHOCH3 groups in the polysaccharides of chitin, while Zn2+ selectively bonded to a fraction of -NH2 groups in cystine and phenylalanine. The mycelium-based leather substitute with Zn cross-linking exhibited impressive tensile strength and tear strength of 7.0 MPa and 16.4 kN/m, respectively, while demonstrating desirable organoleptic properties. The free radical-scavenging capacity of MF-Zn was assessed, revealing a DPPH radical and hydroxyl radical scavenging rates of 39.4% and 52.7%, respectively. By successfully investigating the cross-linking mechanism of mycelial fibres with Zn2+ and obtaining the stabilised mycelium-based leather substitute, this study establishes a fundamental basis for the development of sustainable leather substitutes, meeting the requirements and facilitating significant advancements in low-carbon leather substitute production.

Biofoams with untapped enzymatic potential produced from beer bagasse by indigenous fungal strains

White rot fungi are promising organisms for the production of mycelial-based biofoams, providing a sustainable means of valorizing lignocellulosic wastes. This study explores the utilization of two indigenous fungal species, isolated from Argentina and belonging to the genera Trametes, for producing biofoams from brewery waste. The resulting biofoams exhibited an average density of 0.30 g cm-3, a Young's modulus of approximately 1 MPa, and a compressive stress of around 19 MPa. Additionally, the variation of laccase activity throughout the biofoam production process was evaluated. Surprisingly, residual laccase activity was detected in the biofoams following oven drying at temperatures of 60, 80, and 100 °C. This detection highlights the untapped enzymatic potential of the biofoams and positions them as promising green catalysts for various biotechnological applications.

Harnessing Fungi Signaling in Living Composites

Signaling pathways in fungi offer a profound avenue for harnessing cellular communication and have garnered considerable interest in biomaterial engineering. Fungi respond to environmental stimuli through intricate signaling networks involving biochemical and electrical pathways, yet deciphering these mechanisms remains a challenge. In this review, an overview of fungal biology and their signaling pathways is provided, which can be activated in response to external stimuli and direct fungal growth and orientation. By examining the hyphal structure and the pathways involved in fungal signaling, the current state of recording fungal electrophysiological signals as well as the landscape of fungal biomaterials is explored. Innovative applications are highlighted, from sustainable materials to biomonitoring systems, and an outlook on the future of harnessing fungi signaling in living composites is provided.

Advanced Fungal Biotechnologies in Accomplishing Sustainable Development Goals (SDGs): What Do We Know and What Comes Next?

The present era has witnessed an unprecedented scenario with extreme climate changes, depleting natural resources and rising global food demands and its widespread societal impact. From providing bio-based resources to fulfilling socio-economic necessities, tackling environmental challenges, and ecosystem restoration, microbes exist as integral members of the ecosystem and influence human lives. Microbes demonstrate remarkable potential to adapt and thrive in climatic variations and extreme niches and promote environmental sustainability. It is important to mention that advances in fungal biotechnologies have opened new avenues and significantly contributed to improving human lives through addressing socio-economic challenges. Microbe-based sustainable innovations would likely contribute to the United Nations sustainable development goals (SDGs) by providing affordable energy (use of agro-industrial waste by microbial conversions), reducing economic burdens/affordable living conditions (new opportunities by the creation of bio-based industries for a sustainable living), tackling climatic changes (use of sustainable alternative fuels for reducing carbon footprints), conserving marine life (production of microbe-based bioplastics for safer marine life) and poverty reduction (microbial products), among other microbe-mediated approaches. The article highlights the emerging trends and future directions into how fungal biotechnologies can provide feasible and sustainable solutions to achieve SDGs and address global issues.

A practical guide to the discovery of biomolecules with biostimulant activity

The growing demand for sustainable solutions in agriculture, which are critical for crop productivity and food quality in the face of climate change and the need to reduce agrochemical usage, has brought biostimulants into the spotlight as valuable tools for regenerative agriculture. With their diverse biological activities, biostimulants can contribute to crop growth, nutrient use efficiency, and abiotic stress resilience, as well as to the restoration of soil health. Biomolecules include humic substances, protein lysates, phenolics, and carbohydrates have undergone thorough investigation because of their demonstrated biostimulant activities. Here, we review the process of the discovery and development of extract-based biostimulants, and propose a practical step-by-step pipeline that starts with initial identification of biomolecules, followed by extraction and isolation, determination of bioactivity, identification of active compound(s), elucidation of mechanisms, formulation, and assessment of effectiveness. The different steps generate a roadmap that aims to expedite the transfer of interdisciplinary knowledge from laboratory-scale studies to pilot-scale production in practical scenarios that are aligned with the prevailing regulatory frameworks.

Effects of Incorporating Ionic Crosslinking on 3D Printing of Biomass-Fungi Composite Materials

Biomass-fungi composite materials primarily consist of biomass particles (sourced from agricultural residues) and a network of fungal hyphae that bind the biomass particles together. These materials have potential applications across diverse industries, such as packaging, furniture, and construction. 3D printing offers a new approach to manufacturing parts using biomass-fungi composite materials, as an alternative to traditional molding-based methods. However, there are challenges in producing parts with desired quality (for example, geometric accuracy after printing and height shrinkage several days after printing) by using 3D printing-based methods. This paper introduces an innovative approach to enhance part quality by incorporating ionic crosslinking into the 3D printing-based methods. While ionic crosslinking has been explored in hydrogel-based bioprinting, its application in biomass-fungi composite materials has not been reported. Using sodium alginate (SA) as the hydrogel and calcium chloride as the crosslinking agent, this paper investigates their effects on quality (geometric accuracy and height shrinkage) of 3D printed samples and physiochemical characteristics (rheological, chemical, and texture properties) of biomass-fungi composite materials. Results show that increasing SA concentration led to significant improvements in both geometric accuracy and height shrinkage of 3D printed samples. Moreover, crosslinking exposure significantly enhanced hardness of the biomass-fungi mixture samples prepared for texture profile analysis, while the inclusion of SA notably improved cohesiveness and springiness of the biomass-fungi mixture samples. Furthermore, Fourier transform infrared spectroscopy confirms the occurrence of ionic crosslinking within 3D printed samples. Results from this study can be used as a reference for developing new biomass-fungi mixtures for 3D printing in the future.

A Review Delving into the Factors Influencing Mycelium-Based Green Composites (MBCs) Production and Their Properties for Long-Term Sustainability Targets

Mycelium-based green composites (MBCs) represent an eco-friendly material innovation with vast potential across diverse applications. This paper provides a thorough review of the factors influencing the production and properties of MBCs, with a particular focus on interdisciplinary collaboration and long-term sustainability goals. It delves into critical aspects such as fungal species selection, substrate type selection, substrate preparation, optimal conditions, dehydrating methods, post-processing techniques, mold design, sterilization processes, cost comparison, key recommendations, and other necessary factors. Regarding fungal species selection, the paper highlights the significance of considering factors like mycelium species, decay type, hyphal network systems, growth rate, and bonding properties in ensuring the safety and suitability of MBCs fabrication. Substrate type selection is discussed, emphasizing the importance of chemical characteristics such as cellulose, hemicellulose, lignin content, pH, organic carbon, total nitrogen, and the C: N ratio in determining mycelium growth and MBC properties. Substrate preparation methods, optimal growth conditions, and post-processing techniques are thoroughly examined, along with their impacts on MBCs quality and performance. Moreover, the paper discusses the importance of designing molds and implementing effective sterilization processes to ensure clean environments for mycelium growth. It also evaluates the costs associated with MBCs production compared to traditional materials, highlighting potential cost savings and economic advantages. Additionally, the paper provides key recommendations and precautions for improving MBC properties, including addressing fungal strain degeneration, encouraging research collaboration, establishing biosecurity protocols, ensuring regulatory compliance, optimizing storage conditions, implementing waste management practices, conducting life cycle assessments, and suggesting parameters for desirable MBC properties. Overall, this review offers valuable insights into the complex interplay of factors influencing MBCs production and provides guidance for optimizing processes to achieve sustainable, high-quality composites for diverse applications.

Fabrication of Living Entangled Network Composites Enabled by Mycelium

Organic polymer-based composite materials with favorable mechanical performance and functionalities are keystones to various modern industries; however, the environmental pollution stemming from their processing poses a great challenge. In this study, by finding an autonomous phase separating ability of fungal mycelium, a new material fabrication approach is introduced that leverages such biological metabolism-driven, mycelial growth-induced phase separation to bypass high-energy cost and labor-intensive synthetic methods. The resulting self-regenerative composites, featuring an entangled network structure of mycelium and assembled organic polymers, exhibit remarkable self-healing properties, being capable of reversing complete separation and restoring ≈90% of the original strength. These composites further show exceptional mechanical strength, with a high specific strength of 8.15 MPa g.cm-3, and low water absorption properties (≈33% after 15 days of immersion). This approach spearheads the development of state-of-the-art living composites, which directly utilize bioactive materials to "self-grow" into materials endowed with exceptional mechanical and functional properties.

The chemotrophic behaviour of Aspergillus niger: Mapping hyphal filaments during chemo-sensing; the first step towards directed materials formation

In the development of fungal based materials for applications in construction through to biomedical materials and fashion, understanding how to regulate and direct growth is key for gaining control over the form of material generated. Here, we show how simple 'chemical food' cues can be used to manipulate the growth of fungal networks by taking Aspergillus niger as an exemplar species. Chemotrophic responses towards a range of nitrogen and carbon containing biomolecules including amino acids, sugars and sugar alcohols were quantified in terms of chemotrophic index (CI) under a range of basal media compositions (low and high concentrations of N and C sources). Growth of filamentous networks was followed using fluorescence microscopy at single time points and during growth by an AI analytical approach to explore chemo sensing behaviour of the fungus when exposed to pairs (C-C, C-N, N-N) of biomolecules simultaneously. Data suggests that the directive growth of A. niger can be controlled towards simple biomolecules with CI values giving a good approximation for expected growth under a range of growth conditions. This is a first step towards identifying conditions for researcher-led directed growth of hyphae to make mycelial mats with tuneable morphological, physicochemical, and mechanical characteristics.

High-Performance Engineered Composites Biofabrication Using Fungi

Various natural polymers offer sustainable alternatives to petroleum-based adhesives, enabling the creation of high-performance engineered materials. However, additional chemical modifications and complicated manufacturing procedures remain unavoidable. Here, a sustainable high-performance engineered composite that benefits from bonding strategies with multiple energy dissipation mechanisms dominated by chemical adhesion and mechanical interlocking is demonstrated via the fungal smart creative platform. Chemical adhesion is predominantly facilitated by the extracellular polymeric substrates and glycosylated proteins present in the fungal outer cell walls. The dynamic feature of non-covalent interactions represented by hydrogen bonding endows the composite with extensive unique properties including healing, recyclability, and scalable manufacturing. Mechanical interlocking involves multiple mycelial networks (elastic modulus of 2.8 GPa) binding substrates, and the fungal inner wall skeleton composed of chitin and β-glucan imparts product stability. The physicochemical properties of composite (modulus of elasticity of 1455.3 MPa, internal bond strength of 0.55 MPa, hardness of 82.8, and contact angle of 110.2°) are comparable or even superior to those of engineered lignocellulosic materials created using petroleum-based polymers or bioadhesives. High-performance composite biofabrication using fungi may inspire the creation of other sustainable engineered materials with the assistance of the extraordinary capabilities of living organisms.

Functional analysis of basidiomycete specific chitin synthase genes in the agaricomycete fungus Pleurotus ostreatus

Chitin is an essential structural component of fungal cell walls composed of transmembrane proteins called chitin synthases (CHSs), which have a large range of reported effects in ascomycetes; however, are poorly understood in agaricomycetes. In this study, evolutionary and molecular genetic analyses of chs genes were conducted using genomic information from nine ascomycete and six basidiomycete species. The results support the existence of seven previously classified chs clades and the discovery of three novel basidiomycete-specific clades (BI-BIII). The agaricomycete fungus Pleurotus ostreatus was observed to have nine putative chs genes, four of which were basidiomycete-specific. Three of these basidiomycete specific genes were disrupted in the P. ostreatus 20b strain (ku80 disruptant) through homologous recombination and transformants were obtained (Δchsb2, Δchsb3, and Δchsb4). Despite numerous transformations Δchsb1 was unobtainable, suggesting disruption of this gene causes a crucial negative effect in P. ostreatus. Disruption of these chsb2-4 genes caused sparser mycelia with rougher surfaces and shorter aerial hyphae. They also caused increased sensitivity to cell wall and membrane stress, thinner cell walls, and overexpression of other chitin and glucan synthases. These genes have distinct roles in the structural formation of aerial hyphae and cell walls, which are important for understanding basidiomycete evolution in filamentous fungi.

Biological pretreatment with white rot fungi for preparing hierarchical porous carbon from Banlangen residues with high performance for supercapacitors and dye adsorption

White rot fungi possess superior infiltrability and biodegradability on lignocellulosic substrates, allowing them to form tailored microstructures which are conducive to efficient carbonization and chemical activation. The present research employed white rot fungus pretreatment as a viable approach for preparing porous carbon from Banlangen residues. The resultant F-A-BLGR-PC prepared by pretreating Banlangen residues with white rot fungi followed by carbonization and activation has a hierarchical porous structure with a high specific surface area of 898 m2 g-1, which is 43.4% greater than that of the unprocessed sample (R-BLGR-PC). When used as an electrode for supercapacitors, the F-A-BLGR-PC demonstrated a high specific capacitance of 308 F g-1 at 0.5 A g-1 in 6 M KOH electrolyte in three-electrode configuration. Moreover, the F-A-BLGR-PC based symmetric supercapacitor device achieved a superb cyclic stability with no obvious capacitance decay after 20,000 cycles at 5 A g-1 in 1 M Na2SO4 electrolyte. Additionally, the F-A-BLGR-PC sample was found to be an ideal adsorbent for removing methyl orange (MO) from water, exhibiting an adsorption ability of 173.4 mg g-1 and a maximum removal rate of 86.6%. This study offers a promising method for the preparation of a porous carbon with a high specific surface area in a biological way using white rot fungi pretreatment, and the derived carbon can not only be applied in energy storage but also in environmental remediation, catalysis, and so on.

3D Bioprinting of Food Grade Hydrogel Infused with Living Pleurotus ostreatus Mycelium in Non-sterile Conditions

Mycelium is the root-like network of fungi. Mycelium biocomposites prepared by template replication (molding) can function as environmentally friendly alternatives to conventional polystyrene foams, which are energy- and carbon-intensive to manufacture. Recently, several studies have shown that 3D bioprinting technologies can be used to produce high value functional mycelium products with intricate geometries that are otherwise difficult or impossible to achieve via template replication. A diverse range of nutrients, thickeners, and gelling agents can be combined to produce hydrogels suitable for 3D bioprinting. 3D bioprinting with hydrogel formulations infused with living fungi produces engineered living materials that continue to grow after bioprinting is complete. However, a hydrogel formulation optimized for intricate 3D bioprinting of Pleurotus ostreatus mycelium, which is among the strains most commonly used in mycelium biocomposite fabrication, has yet to be described. Here, we design and evaluate a versatile hydrogel formulation consisting of malt extract (nutrient), carboxymethylcellulose and cornstarch (thickeners), and agar (gelling agent), all of which are easily sourced food grade reagents. We also outline a reproducible workflow to infuse this hydrogel with P. ostreatus liquid culture for 3D bioprinting of intricate structures comprised of living P. ostreatus mycelium and characterize the changes in height and mass as well as hardness of the prints during mycelium growth. Finally, we demonstrate that the workflow does not require a sterile bioprinting environment to achieve successful prints and that the same mycelium-infused hydrogel can be supplemented with additives such as sawdust to produce mycelium biocomposite objects. These findings demonstrate that 3D bioprinting using mycelium-based feedstocks could be a promising biofabrication technique to produce engineered living materials for applications such as mushroom cultivation, food preparation, or construction of the built environment.

Pre- and Postharvest Strategies for Pleurotus ostreatus Mushroom in a Circular Economy Approach

Mushroom cultivation presents a viable solution for utilizing agro-industrial byproducts as substrates for growth. This process enables the transformation of low-economic-value waste into nutritional foods. Enhancing the yield and quality of preharvest edible mushrooms, along with effectively preserving postharvest mushrooms, stands as a significant challenge in advancing the industry. Implementing pre- and postharvest strategies for Pleurotus ostreatus (Jacq.) P. Kumm (oyster mushroom) within a circular economy framework involves optimizing resource use, minimizing waste, and creating a sustainable and environmentally friendly production system. This review aimed to analyze the development and innovation of the different themes and trends by bibliometric analysis with a critical literature review. Furthermore, this review outlines the cultivation techniques for Pleurotus ostreatus, encompassing preharvest steps such as spawn production, substrate preparation, and the entire mushroom growth process, which includes substrate colonization, fruiting, harvesting, and, finally, the postharvest. While novel methodologies are being explored for maintaining quality and extending shelf-life, the evaluation of the environmental impact of the entire mushroom production to identify areas for improvement is needed. By integrating this knowledge, strategies can be developed for a more sustainable and circular approach to Pleurotus ostreatus mushroom cultivation, promoting environmental stewardship and long-term viability in this industry.

Effects of Environmental and Nutritional Conditions on Mycelium Growth of Three Basidiomycota

In recent decades, an enormous potential of fungal-based products with characteristics equal to, or even outperforming, classic petroleum-derived products has been acknowledged. The production of these new materials uses mycelium, a root-like structure of fungi consisting of a mass of branching, thread-like hyphae. Optimizing the production of mycelium-based materials and fungal growth under technical conditions needs to be further investigated. The main objective of this study was to select fast-growing fungi and identify optimized incubation conditions to obtain a dense mycelium mat in a short time. Further, the influence of the initial substrate characteristics on hyphae expansion was determined. Fungal isolates of Ganoderma lucidum, Pleurotus ostreatus, and Trametes versicolor were cultivated for seven days on substrate mixtures consisting of various proportions of pine bark and cotton fibers. Furthermore, the substrates were mixed with 0, 2, and 5 wt.% calcium carbonate (CaCO3), and the incubator was flushed with 0, 5, and 10 vol.% carbon dioxide (CO2). All samples grew in the dark at 26 °C and a relative humidity of 80%. Evaluation of growth rate shows that cotton fiber-rich substrates performed best for all investigated fungi. Although Pleurotus ostreatus and Trametes versicolor showed comparatively high growth rates of up to 5.4 and 5.3 mm d-1, respectively, mycelium density was thin and transparent. Ganoderma lucidum showed a significantly denser mycelium at a maximum growth rate of 3.3 mm d-1 on a cotton fiber-rich substrate (75 wt.%) without CaCO3 but flushed with 5 vol.% CO2 during incubation.

Robust myco-composites: a biocomposite platform for versatile hybrid-living materials

Fungal mycelium, a living network of filamentous threads, thrives on lignocellulosic waste and exhibits rapid growth, hydrophobicity, and intrinsic regeneration, offering a potential means to create next-generation sustainable and functional composites. However, existing hybrid-living mycelium composites (myco-composites) are tremendously constrained by conventional mold-based manufacturing processes, which are only compatible with simple geometries and coarse biomass substrates that enable gas exchange. Here we introduce a class of structural myco-composites manufactured with a novel platform that harnesses high-resolution biocomposite additive manufacturing and robust mycelium colonization with indirect inoculation. We leverage principles of hierarchical composite design and selective nutritional provision to create a robust myco-composite that is scalable, tunable, and compatible with complex geometries. To illustrate the versatility of this platform, we characterize the impact of mycelium colonization on mechanical and surface properties of the composite. We found that our method yields the strongest mycelium composite reported to date with a modulus of 160 MPa and tensile strength of 0.72 MPa, which represents over a 15-fold improvement over typical mycelium composites, and further demonstrate unique applications with fabrication of foldable bio-welded containers and flexible mycelium textiles. This study bridges the gap between biocomposite and hybrid-living materials research, opening the door to advanced structural mycelium applications and demonstrating a novel platform for development of diverse hybrid-living materials.

Use of sawdust for production of ligninolytic enzymes by white-rot fungi and pharmaceutical removal

Use of white-rot fungi for enzyme-based bioremediation of wastewater is of high interest. These fungi produce considerable amounts of extracellular ligninolytic enzymes during solid-state fermentation on lignocellulosic materials such as straw and sawdust. We used pure sawdust colonized by Pleurotus ostreatus, Trametes versicolor, and Ganoderma lucidum for extraction of ligninolytic enzymes in aqueous suspension. Crude enzyme suspensions of the three fungi, with laccase activity range 12-43 U/L and manganese peroxidase activity range 5-55 U/L, were evaluated for degradation of 11 selected pharmaceuticals spiked at environmentally relevant concentrations. Sulfamethoxazole was removed significantly in all treatments. The crude enzyme suspension from P. ostreatus achieved degradation of wider range of pharmaceuticals when the enzyme activity was increased. Brief homogenization of the colonized sawdust was also observed to be favorable, resulting in significant reductions after a short exposure of 5 min. The highest reduction was observed for sulfamethoxazole which was reduced by 84% compared to an autoclaved control without enzyme activity and for trimethoprim which was reduced by 60%. The compounds metoprolol, lidocaine, and venlafaxine were reduced by approximately 30% compared to the control. Overall, this study confirmed the potential of low-cost lignocellulosic material as a substrate for production of enzymes from white-rot fungi. However, monitoring over time in bioreactors revealed a rapid decrease in enzymatic ligninolytic activity.

Heavy Metal Remediation by Dry Mycelium Membranes: Approaches to Sustainable Lead Remediation in Water

Lead contamination poses significant and lasting health risks, particularly in children. This study explores the efficacy of dried mycelium membranes, distinct from live fungal biomass, for the remediation of lead (Pb(II)) in water. Dried mycelium offers unique advantages, including environmental resilience, ease of handling, biodegradability, and mechanical reliability. The study explores Pb(II) removal mechanisms through sorption and mineralization by dried mycelium hyphae in aqueous solutions. The sorption isotherm studies reveal a high Pb(II) removal efficiency, exceeding 95% for concentrations below 1000 ppm and ∼63% above 1500 ppm, primarily driven by electrostatic interactions. The measured infrared peak shifts and the pseudo-second-order kinetics for sorption suggests a correlation between sorption capacity and the density of interacting functional groups. The study also explores novel surface functionalization of the mycelium network with phosphate to enhance Pb(II) removal, which enables remediation efficiencies >95% for concentrations above 1500 ppm. Scanning electron microscopy images show a pH-dependent formation of Pb-based crystals uniformly deposited throughout the entire mycelium network. Continuous cross-flow filtration tests employing a dried mycelium membrane demonstrate its efficacy as a microporous membrane for Pb(II) removal, reaching remediation efficiency of 85-90% at the highest Pb(II) concentrations. These findings suggest that dried mycelium membranes can be a viable alternative to synthetic membranes in heavy metal remediation, with potential environmental and water treatment applications.

"You Are What You Eat": How Fungal Adaptation Can Be Leveraged toward Myco-Material Properties

Fungi adapt to their surroundings, modifying their behaviors and composition under different conditions like nutrient availability and environmental stress. This perspective examines how a basic understanding of fungal genetics and the different ways that fungi can be influenced by their surroundings can be leveraged toward the production of functional mycelium materials. Simply put, within the constraints of a given genetic script, both the quality and quantity of fungal mycelium are shaped by what they eat and where they grow. These two levers, encompassing their global growth environment, can be turned toward different materials outcomes. The final properties of myco-materials are thus intimately shaped by the conditions of their growth, enabling the design of new biobased and biodegradable material constructions for applications that have traditionally relied on petroleum-based chemicals.This perspective highlights aspects of fungal genetics and environmental adaptation that have potential materials science implications, along the way touching on key studies, both to situate the state of the art within the field and to punctuate the viewpoints of the authors. Finally, this work ends with future perspectives, reinforcing key topics deemed important to consider in emerging myco-materials research.