Showing papers on "Mycelium published in 2021"

Synthesis and Applications of Fungal Mycelium-based Advanced Functional Materials

Abstract: Over the last couple of decades, the introduction of living systems to material science for the synthesis of functional materials from biological resources is receiving immense consideration. This is also in accordance with the need for green and sustainable development of new materials. For example, the growing concerns of the degradation of synthetic plastics are shifting the direction of materials-related research to the use of polymeric materials acquired from renewable resources. For example, the fungal mycelium-based materials are produced by growing the vegetative part of mushroom-forming fungi on different organic substrates. Such fungi are known for their ability to degrade agricultural wastes such as straws and sawdust. The mycelium-based composites having tailored structural, physical, chemical, mechanical, and biological properties are relying on the strain, feeding substrate, and the manufacturing process. The mycelium cell wall mainly contains the chitin, glucans, proteins, and lipids, whose concentrations depend upon the feeding substrate that ultimately defines the final properties of the synthesized materials. The mycelium-based functional materials with tunable properties are synthesized by selecting the desired components and the synthesis method. The pure and composites of stiff, elastic, porous, less dense, fast-growing, and low-cost mycelium-derived materials with efficient antimicrobial, antioxidant, and skin whitening properties pave their way in various applications such as construction, packaging, medicine, and cosmetics. This review describes the synthesis and structural organization of mycelium-based materials. It further discusses the effect of different factors on the material properties. Finally, it summarizes different applications of mycelium-based materials in medicine, cosmetics, packaging, and construction fields.

Material Function of Mycelium-Based Bio-Composite: A Review

Abstract: Mycelium-based bio-composites materials have been invented and widely applied to different areas including the construction industry, manufacturing industry, agriculture, and biomedical. As the vegetative part of a fungus, mycelium has the unique capability to utilize agricultural crop waste (e.g., sugarcane bagasse, rice husks, cotton stalks, straw and stover) as substrates for the growth of its network, which integrates the wastes from pieces to continuous composites without energy input nor generating extra waste. Their low-cost and environmentally friendly features attract interest in its research and commercialization. For example, mycelium-based foam and sandwich composites have been actively developed for construction structures. It can be used as synthetic planar materials (e.g., plastic films and sheets), larger low-density objects (e.g., synthetic foams and plastics), and semi-structural materials (e.g., paneling, flooring, furniture, decking). It is shown that the material function of these composites can be further tuned by controlling the species of fungus, the growing conditions, and the post-growth processing method to meet a specific mechanical requirement in applications (e.g., structural support, acoustic and thermal insulation). Moreover, mycelium can be used to produce chitin and chitosan, which have been applied to clinical trials for wound healing, showing the potential for biomedical applications. Given the strong potential and multiple advantages of such a material, we are interested in studying them in-depth and review the current progress of their related study in this review paper.

Carbon investment into mobilization of mineral and organic phosphorus by arbuscular mycorrhiza

Abstract: To overcome phosphorus (P) deficiency, about 80% of plant species establish symbiosis with arbuscular mycorrhizal fungi (AMF), which in return constitute a major sink of photosynthates. Information on whether plant carbon (C) allocation towards AMF increases with declining availability of the P source is limited. We offered orthophosphate (OP), apatite (AP), or phytic acid (PA) as the only P source available to arbuscular mycorrhiza (AM) (Solanum lycopersicum x Rhizophagus irregularis) in a mesocosm experiment, where the fungi had exclusive access to each P source. After exposure, we determined P contents in the plant, related these to the overall C budget of the system, including the organic C (OC) contents, the respired CO2, the phospholipid fatty acid (PLFA) 16:1ω5c (extraradical mycelium), and the neutral fatty acid (NLFA) 16:1ω5c (energy storage) at the fungal compartment. Arbuscular mycorrhizal (AM) plants incorporated P derived from the three P sources through the mycorrhizal pathway, but did this with differing C-P trading costs. The mobilization of PA and AP by the AM plant entailed larger mycelium infrastructure and significantly larger respiratory losses of CO2, in comparison with the utilization of the readily soluble OP. Our study thus suggests that AM plants invest larger C amounts into their fungal partners at lower P availability. This larger C flux to the AM fungi might also lead to larger soil organic C contents, in the course of forming larger AM biomass under P-limiting conditions.

Production and turnover of mycorrhizal soil mycelium relate to variation in drought conditions in Mediterranean Pinus pinaster, Pinus sylvestris and Quercus ilex forests.

Abstract: In forests, ectomycorrhizal mycelium is pivotal for driving soil carbon and nutrient cycles, but how ectomycorrhizal mycelial dynamics vary in ecosystems with drought periods is unknown. We quantified the production and turnover of mycorrhizal mycelium in Mediterranean Pinus pinaster, Pinus sylvestris and Quercus ilex forests and related the estimates to standardised precipitation index (SPI), to study how mycelial dynamics relates to tree species and drought-moisture conditions. Production and turnover of mycelium was estimated between July and February, by quantifying the fungal biomass (ergosterol) in ingrowth mesh bags and using statistical modelling. SPI for time scales of 1-3 months was calculated from precipitation records and precipitation data over the study period. Forests dominated by Pinus trees displayed higher biomass but were seasonally more variable, as opposed to Q. ilex forests where the mycelial biomass remained lower and stable over the season. Production and turnover, respectively, varied between 1.4-5.9 kg ha-1 d-1 and 7.2-9.9 times yr-1 over the different forest types and were positively correlated with 2-month and 3-month SPI over the study period. Our results demonstrated that mycorrhizal mycelial biomass varied with season and tree species and we speculate that production and turnover are related to physiology and plant host performance during drought.

Antifungal efficacy of Moringa oleifera leaf and seed extracts against Botrytis cinerea causing gray mold disease of tomato (Solanum lycopersicum L.).

Abstract: Drawbacks associated with the use of chemical fungicides to control plant pathogenic fungi such as Botrytis cinerea stimulate the need for alternatives. Therefore, the present study was carried out to determine the antifungal potentials of Moringa oleifera extracts against B. cinerea. Phytochemical analysis using qualitative chemical tests revealed the presence of huge amount of crucial phytochemicals compounds like phenolic compounds, alkaloids and saponins in the M. oleifera leaf extract. Antifungal bioassay of the crude extracts indicated better mycelial growth inhibition by methanol leaf extract (99%). The minimum inhibitory concentration (MIC) was 5 mg/ml with 100% spore germination inhibition and minimum fungicidal concentration (MFC) was 10 mg/ml with 98.10% mycelial growth inhibition using broth micro dilution and poisoned food techniques. Gas chromatography-mass spectrometry (GC-MS) analysis led to the identification of 67 volatile chemical compounds in the leaf extract with 6-decenoic acid (Z)- (19.87%) was the predominant compound. Further chemical elucidation of the crude extracts performed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) showed the presence of non-volatile chemical compounds, mostly flavones, flavonoids and phenolic acids (i.e. quercetin and kaempferol). Scanning electron microscopy and transmission electron microscopy analysis showed positive effect of M. oleifera leaf extract on the treated conidia and mycelium of B. cinerea. Findings revealed that irreversible surface and ultra-structural changes with severe detrimental effects on conidia and mycelium morphology compared to control treatment. Overall findings suggested that M. oleifera leaf extract is a promising candidate for biological control of fungal pathogens, thus limiting overdependence on chemical fungicides.

Novel metabolites from Bacillus safensis and their antifungal property against Alternaria alternata

Abstract: Plant growth promoting rhizobacteria offer an effective and eco-sustainable solution to protect crops against phytopathogens. In the present study, Bacillus safensis STJP (NAIMCC-B-02323) from the rhizospheric soil of Stevia rebaudiana showed strong biocontrol activity against phytopathogen, Alternaria alternata. B. safensis STJP produced antifungal volatile organic compounds (AVOC). In the presence of AVOC, there was no conidia germination, mycelium growth was inhibited, and hyphae ruptured as observed by scanning electron microscopy. When mycelium of the fungus from bacterial treated plate was transferred into fresh potato dextrose agar plate, A. alternata could not grow. Extracted AVOC from B. safensis STJP were identified by thin-layer chromatography (TLC), Fourier-transform-infrared (FTIR) spectroscopy and gas-chromatography–mass spectrometry (GC–MS). In total 25 bacterial metabolites were identified by GC–MS analysis having alcohol, alkane, phenol, alkyl halide and aromatic compounds. Five of these (phenol, 2,4-bis (1,1-dimethylethyl)-, 3-hexadecanol, pyrrolo(1,2-a)pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)-, 5,10-diethoxy-2,3,7,8-tetrahydro-1H,6H-dipyrrolo(1,2-a:1′,2′-d)pyrazine and hexadecanoic acid) inhibited the mycelium growth, controlling spore formation and conidia germination of A. alternata. This study concluded that AVOC producing B. safensis can be used as a green-fungicide against A. alternata. Bacterial metabolites could pave the way for the development of next generation biopesticides. This can be a reliable technology to enhance the quality and reliability of biopesticides.

All-Natural Smart Mycelium Surface with Tunable Wettability

Abstract: A naturally occurring smart mycelium surface with tunable wettability is demonstrated. The commercially produced mycelium foam shows a natural hydrophobic and nonabsorbent surface with water contac...

Living mycelium composites discern weights via patterns of electrical activity

Abstract: Fungal construction materials—substrates colonised by mycelium—are getting increased recognition as viable ecologically friendly alternatives to conventional building materials. A functionality of the constructions made from fungal materials would be enriched if blocks with living mycelium, known for their ability to respond to chemical, optical and tactile stimuli, were inserted. We investigated how large blocks of substrates colonised with mycelium of Ganoderma resinaceum responded to stimulation with heavy weights. We analysed details of the electrical responses to the stimulation with weights and show that ON and OFF stimuli can be discriminated by the living mycelium composites and that a habituation to the stimulation occurs. Novelty of the results cast in the reporting on changes in electrical spiking activity of mycelium bound composites in response to a heavy loads.

Investigations into the Development of a Mycelium Biocomposite to Substitute Polystyrene in Packaging Applications

Abstract: Expanded polystyrene is a versatile synthetic polymer that has a remarkable presence in packaging applications. It is also non-biodegradable in nature which makes them one of the worst solid pollutants that affect the environment. This paper focuses on the possibility of developing an eco-friendly packaging material with mycelium as a binder in a sawdust matrix, and to study the extent up to which these composites are reliable in substituting polystyrene for sustainable packaging applications. The combustion test using a respirable dust sampler has revealed the number of toxic combustion products liberated while burning expanded polystyrene samples. Mycelium fibres were grown from oyster mushrooms, and the analysis of scanning electron microscope images has ensured the growth of mycelium without contamination. Characterization of the newly developed mycelium composite material was done using various techniques, and the results were compared against those of polystyrene. Fourier transform infrared spectroscopy analysis was used to determine the composition and morphology, whereas the thermal behaviour was analysed through tests such as thermogravimetric analysis and differential scanning calorimetry. An X-ray diffraction test was also conducted to identify the compounds present in the samples. The investigation shed light upon the possibility of using the newly developed mycelium bio-composite material to substitute polystyrene as a packaging material.

Electrical activity of fungi: Spikes detection and complexity analysis.

Abstract: Oyster fungi Pleurotus djamor generate actin potential like spikes of electrical potential The trains of spikes might manifest propagation of growing mycelium in a substrate, transportation of nutrients and metabolites and communication processes in the mycelium network The spiking activity of the mycelium networks is highly variable compared to neural activity and therefore can not be analysed by standard tools from neuroscience We propose original techniques for detecting and classifying the spiking activity of fungi Using these techniques, we analyse the information-theoretic complexity of the fungal electrical activity The results can pave ways for future research on sensorial fusion and decision making of fungi

Effect of growth factors on the production of mycelium-based biofoam

Abstract: Mycelium-based biofoam has the potential to become an alternative to petroleum-polymeric based-foam by utilising fungal mycelium and lignocellulosic material as the matrix and substrate, respectively. The lignocellulosic materials, which were rice husk, sawdust, and sugarcane bagasse, which is crucial for the production of biofoam, were tested as a substrate for Pleurotus ostreatus mycelium growth during the screening procedure. Three growth factors were varied during mycelium-based biofoam production: incubation temperature, spawn loading, and moisture content. In this study, rice husk was the ideal substrate in the production of mycelium biofoam compared to other fungi. The inhibition of P. ostreatus mycelium growth at 30 °C incubation temperature was due to decay and contamination. On the other hand, by varying the growth factor of mycelium biofoam on rice husk, the optimum dry density of mycelium–biofoam was observed at 50% (w/w) moisture content (1.07 g/cm3), while the optimum compressive strength was observed at 40% (w/w) spawn loading (1.350 MPa). These results showed that varying the growth factor could influence the mechanical behaviour of the material. The morphology of the biofoam was also observed through a scanning electron microscope. Short and highly entangled tube-like structures and compact filaments forming a material were seen, responsible for the lightness characteristic of the material. The functional group of the biofoam was also determined using a Fourier transform infrared spectrophotometer. A new band of proteins and lipids was detected at 1633 cm−1 and 3280 cm−1 in the biofoam. It clearly shows the chemical nature of feeding substrate responsible for the changes of material spectra. Therefore, this study highlighted that the biodegradable mycelium biofoam of P. ostreatus using rice husk as a substrate is a promising alternative to polymeric foam.

The inhibitory effect of volatile organic compounds produced by Bacillus subtilis CL2 on pathogenic fungi of wolfberry.

Abstract: Bacillus subtilis strain CL2 is antagonistic to wolfberry postharvest pathogenic fungi. In this study, we isolated and screened this strain for in vitro experiments. The result of the two-sealed-base-plates method revealed that volatile organic compounds (VOCs) emitted from the strain CL2 inhibited the hyphal growth of four pathogenic fungi Mucor circinelloides LB1, Fusarium arcuatisporum LB5, Alternaria iridiaustralis LB7, and Colletotrichum fioriniae LB8. After exposure to VOCs for 5 days, the hyphal growth of the pathogen C. fioriniae LB8 was inhibited by 73%. Scanning electron microscopy revealed that the VOCs produced by B. subtilis CL2 caused the mycelium morphology of the pathogenic fungi to deform, twist, fold, and shrink. In the in vivo experiments, we noticed that VOCs could significantly reduce the weight loss rate of wolfberry fruits caused by the pathogenic fungus M. circinelloides LB1 and that the decay incidence rate were caused by the pathogenic fungi F. arcuatisporum LB5, A. iridiaustralis LB7, and C. fioriniae LB8. On the basis of the headspace-gas chromatography-ion mobility spectrometry analysis, seven VOCs produced by strain CL2 were identified. Among them, 2,3-butanedione and 3-methylbutyric acid are the main antifungal active substances. This study investigated the antifungal properties of VOCs produced by the strain CL2 on postharvest pathogenic fungi isolated from wolfberry fruits both in vivo and in vitro, thereby providing the theoretical basis for its future applications.

The Protective Biochemical Properties of Arbuscular Mycorrhiza Extraradical Mycelium in Acidic Soils Are Maintained throughout the Mediterranean Summer Conditions

Abstract: In acidic soils with manganese (Mn) toxicity, arbuscular mycorrhizal fungi (AMF) can improve plant host growth by enhancing nutrition and protecting against environmental stress. The intact extraradical mycelium (ERM) of AMF is able to survive Mediterranean summer conditions and provide an earlier colonization of winter crops. This study evaluated if summer season conditions hindered the beneficial effects of wheat colonization by the intact ERM associated with a native plant, in acidic soil. Wheat was grown in soil with intact or disrupted ERM associated with Ornithopus compressus (ORN), developed for 7 or 24 weeks, to simulate ERM summer survival. The activity of antioxidant enzymes was determined, and the quantitative analysis of Mn and macronutrients was performed by inductively coupled plasma mass spectrometry (ICP-MS), in wheat shoots and respective subcellular fractions. Wheat colonization by intact ERM decreased shoot Mn concentration but increased the proportion of Mn in the apoplast. Overall, antioxidant enzymatic activity decreased but the proportion of Mn-superoxide dismutase activity over the remaining isoforms increased, suggesting its important role in the AMF-mediated mitigation of Mn toxicity. Summer conditions did not substantially reduce the benefits provided by ORN ERM. A no-till strategy allied to the development of native microbiota can contribute to the sustainable optimization of acidic soil use.

Role of endophytic Penicillium species and Pseudomonas monteilii in inducing the systemic resistance in okra against root rotting fungi and their effect on some physiochemical properties of okra fruit.

Abstract: Aims The efficacy of three isolates of endophytic Penicillium species that have shown significant suppressive effect on root rotting fungi in our previous study were further evaluated in pots and field plot experiments for their effect on root diseases of okra, induction of systemic resistance and physiochemical properties of okra fruit. Methods and results Aqueous suspensions of endophytic Penicillium and Pseudomonas monteilii were applied in pots and field plots using okra as test plant. Data on the fungal infection of roots, plant growth, plant resistance markers like polyphenol, salicylic acid and antioxidant status of plant were determined. These isolates significantly suppressed root diseases and induced systemic resistance via increasing level of resistance markers, polyphenol and salicylic acid besides improving antioxidant activity of Penicillium and P. monteilii-treated plants as compared to control plants. GC-MS analysis of n-hexane extract of mycelium of P. nigricans revealed the presence of 15 different volatile compounds. Conclusions Endophytic Penicillium and P. monteilii have potential against root-infecting fungi of okra and can improve plant growth and yield. Significance and impact of the study Endophytic Penicillium species and P. monteilii can suppress root rotting fungi by direct mechanism or induction of systemic resistance in plants.

The Fungi-specific histone Acetyltransferase Rtt109 mediates morphogenesis, Aflatoxin synthesis and pathogenicity in Aspergillus flavus by acetylating H3K9.

Abstract: Aspergillus flavus is a common saprophytic filamentous fungus that produces the highly toxic natural compound aflatoxin during its growth process Synthesis of the aflatoxins, which can contaminate food crops causing huge losses to the agricultural economy, is often regulated by epigenetic modification, such as the histone acetyltransferase In this study, we used Aspergillus flavus as an experimental model to construct the acetyltransferase gene rtt109 knockout strain (△rtt109) and its complementary strain (△rtt109·com) by homologous recombination The growth of △rtt109 was significantly suppressed compared to the wild type (WT) strain and the △rtt109·com strain The sclerotium of △rtt109 grew smaller, and the amount of sclerotia generated by △rtt109 was significantly reduced The number of conidiums of △rtt109 was significantly reduced, especially on the yeast extract sucrose (YES) solid medium The amount of aflatoxins synthesized by △rtt109 in the PDB liquid medium was significantly decreased We also found that the △rtt109 strain was extremely sensitive to DNA damage stress Through the maize seed infection experiment, we found that the growth of △rtt109 on the surface of affected corn was largely reduced, and the amount of aerial mycelium decreased significantly, which was consistent with the results on the artificial medium We further found that H3K9 was the acetylated target of Rtt109 in A flavus In conclusion, Rtt109 participated in the growth, conidium formation, sclerotia generation, aflatoxin synthesis, environmental stress response, regulation of infection of A flavus The results from this study of rtt109 showed data for acetylation in the regulation of life processes and provided a new thought regarding the prevention and control of A flavus hazards

The physiological response of Ectomycorrhizal fungus Lepista sordida to Cd and Cu stress.

Abstract: Ectomycorrhizal fungi (ECMF) can develop the resistance of host plants to heavy metal stress. However, little is known about the response of ECMF to heavy metal exposure. In this study, the growth and physiological indices of Lepista sordida under Cd and Cu stress were studied. The growth of L. sordida on PDA medium under Cd and Cu stress was observed using scanning electron microscopy (SEM). After the addition of Cd and Cu to the medium, the mycelium started twisting, breaking, sticking together, and even dissolving. In the control group, a good and luxuriant mycelium growth of L. sordida along with the numerous clamp connections was observed. The mycelial biomass decreased with increasing concentrations of heavy metals in a liquid medium. The catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX) activities were also investigated, and the results showed that the Cd and Cu treatments caused a significant increase in the antioxidant enzyme activities. The contents of soluble protein, soluble sugar, and free proline in L. sordida were investigated, and it was found that the contents initially increased and then decreased with the increasing concentrations of Cd and Cu. However, the content of malondialdehyde (MDA) increased with the increasing concentrations of Cd and Cu. In conclusion, the present study provides a theoretical basis for the better utilization of Ectomycorrhizal fungal resources for the remediation of soil contaminated with heavy metal.

Mycelium-composite panels for atmospheric particulate matter adsorption

Abstract: Mycelium composites grow in a symbiotic relationship with the substrate forming entangled networks of branching fibers. The structure of mycelium resembles filter sheets used in air filtration systems. Owing to their porous character, mycelium composites have been studied and developed as sound absorbent materials, insulation materials, and fire-resistant materials. Herein, we investigated the potential utilization of the filter-like, porous characteristics of mycelium for adsorbing atmospheric particulate matter (PM). First, we compared the PM adsorption performance of mycelium composites grown on four different substrates (hemp, rice straw, lacquer tree wood chips, and oak wood chips) with a widely used architectural exterior material, a stone panel (Pocheon granite). Second, we examined the micro-morphology of the mycelium composite panel surfaces by capturing images at 200x and 1000x using scanning electron microscopy. Third, we examined the water absorption rate of the mycelium composite panels with different substrates. The PM adsorption performance of the mycelium composites were superior to that of the Pocheon granite. The PM adsorption performance of the mycelium composite panels varied depending on the type of the substrate. However, the relationship between the micro-morphology of the surface and the PM adsorption performance could not be defined. We also observed that the mycelium composite panels with the higher PM adsorption performance exhibited a higher rate of water absorption. This study shows that mycelium composite panels have potential to be developed as atmospheric PM adsorbing material.

Improvement of karst soil nutrients by arbuscular mycorrhizal fungi through promoting nutrient release from the litter

Abstract: How arbuscular mycorrhizal (AM) fungi affect litter nutrient release and soil properties in the nutrient-deficient karst soil, is unclear. An experiment was conducted in this study using a dual compartment device composed of a planting compartment (for the Cinnamomum camphora seedlings with or without Funneliformis mosseae fungus) and a litter compartment (with or without the litter of Arthraxon hispidus). The center baffle between the compartments was covered with a double layer of 20-µm or 0.45-µm nylon mesh, which controlled the entrance of AM mycelium into the litter compartment. The results are as follows: AM mycelium significantly increased the mass loss and carbon and nitrogen releases and decreased the nitrogen concentration in the litter. AM mycelium could significantly increase soil organic carbon, total nitrogen and availability of phosphorus during litter decomposition in the litter compartment. Redundancy analysis showed that the effect of AM mycelium on the soil organic carbon, total nitrogen in the litter compartment was closely associated with the increase in carbon and nitrogen release from litter. It was concluded that AM mycelium can enhance litter decomposition and nutrient releases, contributing to greater nutrient input to the soil and then subsequently higher soil organic carbon and nutrient content in the nutrient-poor karst soils. STATEMENT OF NOVELTYThis study firstly estimated the impacts of arbuscular mycorrhizal fungi on litter nutrient releases and soil properties through root external mycelium.