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Pulp Faction: 3d printed material assemblies through microbial biotransformation

The world is currently facing an ecological crisis of
unprecedented scale and urgency and, as the building
sector is a significant contributor to the current state, it
must look towards radical change to achieve a sustainable
practice. The most destructive environmental impact is
found in material extraction, processing and discharge.
This paper presents an alternative to industrially mined
and synthesised materials by utilising biological growth
processes as passive engines for the transformation of
renewable materials. This is achieved through fungal-
lignocellulosic composites which have been developed
along with the design and fabrication processes that are
necessary for their application in the construction
Plant-derived materials are abundantly and sustainably
available on both local and global scales, particularly in
the form of by-products and recycled waste. Additive
fabrication provides an opportunity to create high value
products from this material, but comes with its own
challenges. In particular, most of the strength of the wood
is lost as fibres are ground down so that the material can
pass through the extrusion nozzle. Rather than relying on
thermosetting plastics or synthetic binders, this project
explores the controlled growth of fungal mycelium within
the printed material post-extrusion as a binder of
lignocellulosic biomass.
Fungal-lignocellulosic materials inherit properties from
both wood and mycelium, resulting in lightweight and
strong bio-composites. Generally, they exhibit good
insulative performance for both heat and sound, are
hydrophobic, and have good tension and compression
resistance (Yang et al., 2017; Elsacker, 2019). In addition,
the raw materials for such composites are low in cost,
locally sourced, renewable, and able to capture and store
carbon dioxide.
Mycelium Bio-Composites
The main components of mycelium composites are the
biopolymers cellulose and chitin, followed by lignin and
hemicellulose. Mycelium is the vegetative part of a
fungus, made up from a dense network of long, branching
filamentous structures termed hyphae. The cell wall of the
hyphae is made of chitin – a tough, resilient, inert and
non-water-soluble modified polysaccharide that has
promising potential in biotechnology (Latgé and
Calderon, 2006). When the fungus colonises a substrate,
it first grows on the surface and gradually, depending on
the properties of the material, it spreads its mycelium
throughout it in a complex three-dimensional binding
matrix (Boyce and Andrianopoulos, 2006) (Fig. 4).
During growth, the fungus secretes extracellular
polymeric substances (EPS), which are mainly composed
of polysaccharides and proteins (Gazzé et al., 2013).
Their role is to facilitate growth and allow the anchoring
of the cells on the substrate, acting as a glue between the
hyphae and the substrate. Moreover, EPS allow for the
conglomeration of particles around the hyphae, resulting
in an irreversible fusing of the material (Fig. 2).
3D Bio-Printing
Most precedents using lignocellulosic substrate and
mycelial growth for creating bio-composites use casting
as the means of production, for example: The Living’s
Hy-Fi Tower (Nagy et al., 2015); Block Research Group’s
MycoTree (Heisel et al., 2018); Mogu panels (Appels et al.,
2019). Such methods are relatively straightforward and
therefore well-suited for industrial mass-production.
However, the casting process limits the customisation
of the products as well as geometrical complexity that
can be employed for functional performance. In addition,
the strength of the material is markedly determined by
the extent of the mycelium coverage (Yang et al., 2017).
As this is dependent on oxygen, growth is limited to the
material surface. When cast in solid volume, the mycelium
covers a smaller percentage of the total volume, limiting
the potential strength of the composite.
These limitations can be overcome through the use of
digital additive fabrication which allows for a complex
meso-scale structure, radically increasing the surface
area within a given volume and thus ensuring maximum
distribution of hyphae within the composite.
The strategy of additively fabricating mycelium
composites is not unprecedented in nature. Mound-
building macrotermites have evolved to a symbiotic
existence together with fungus of the genus Termitomyces.
The termites harvest plant-based material and carry it
back to the mound where the regulated internal climate is
suitable for fungi. The fungus processes the plant matter,
turning it into nutrients that both the termites and fungus
live on (Turner, 2005). The fungal combs (Fig. 3) have a
particular geometry which, on the one hand provides
access to the termites for managing the comb, and on the
other enable a convective flow of air and respiratory gases
near the comb surfaces. This flow is facilitated by vertical
channels and assisted by the thermal buoyancy generated
by the metabolic heat of the fungus. The combs are
constructed as an intricately folded and interconnected
sheet with an even thickness of approximately 4mm, likely
corresponding to the depth at which the mycelium can
eectively grow while maintaining access to oxygen. The
fungus comb provided an initial set of assumptions for a
design that could provide a suitable balance of parameters
in the project.
Integrated Research Protocols
The research presented in this article concerns the finding
of a set of processes for additive fabrication of fungal-
lignocellulosic materials and the evaluation of their
suitability for architectural fabrication. The primary
intent was to address the questions that arise from the
interdependencies between these processes through a
transdisciplinary approach. Focus has been on testing
feasibility, building a protocol, and establishing a
foundation for informed speculation.
The research was guided by the following questions:
How can a process of bio-fabrication best be structured to
achieve desirable artefacts? How does the introduction of
fungal mycelium aect the material properties? And how
could the developed processes be utilised for fabrication
at architectural scales?
To answer these questions, the presented work explored
the interconnections between (1) the living system,
(2) the digital fabrication, and (3) the computational
design strategy. Subsequently, a number of material
performance tests were carried out on the resulting
samples. The protocol presented here led to the most
successful outcomes with regards to rate of growth,
extrudability, stability and resulting material properties.
Live Pulp
The pulp consists of a substrate that has been inoculated
with fungus. The substrate was developed to comply with
two primary criteria: its ability to support the growth and
development of the fungus, and its suitability for
fabrication which includes both extrudability and the
stability of the material in the print and growth phases.
The main components of the substrate are fine woodchips,
paper pulp, and kaolin clay, which are mixed with water.
Wood and paper pulp compose the bulk of the material
and provide the nutrients for the fungus; during
incubation, these are partially transformed into fungal
biomass. As the substrate doesn’t have an immediate
bonding agent, it remains unstable during printing.
Therefore, clay was added to the mixture to provide
stability during the fabrication and incubation phases.
The substrate also contains a thickening agent which
allows the solid and liquid components to form a coherent
aggregate (Fig. 10).
Two fungal strains were used in the experiments, a strain
of Byssomerulius corium and a strain of Gloeophyllum sp.
They are both wood decomposers, but follow dierent
strategies of wood decomposition termed white rot and
brown rot, respectively. Both fungal strains were
propagated on a malt-yeast medium. When the mycelial
growth was sucient, the fungus was introduced into the
autoclaved substrate. The inoculated substrate was left for
an incubation period of one week, in which the mycelium
propagated through the substrate and adapted to the new
environment, enabling it to resist contaminants introduced
when sterile conditions were no longer maintained.
1. Sectio n of a column
showing an assembly of
the fungal-lignoc ellulosic
components. Bonding
between th e segments is
proposed to b e achieved
by extrusion of a con nective
tissue consis ting of a
modified vers ion of the
live pulp.
2. Substrate un der
microscope. The different
magnifications showing:
(1) The print layer s
covered in mycelium .
(2) The fusio n of mycelium
and substrate. (3 ) The partial
decomposition of the
cellulose and li gnin fibres
by the fungus .
3. Termitomyces fungus
comb. This symbiotic
structure is ad ditively
assembled by m acrotermites
from dead plant m atter
inoculated wi th fungal
spores. The fungus slowly
digests the pl ant matter
into componen ts which the
termites can inge st as food,
while it simultan eously acts
to regulate the humi dity of
the mound’s intern al climate.
4. Living printe d composite
after two we eks of
3 4
Following the initial incubation, the pulp was 3D printed,
after which it went through a second and longer
incubation period. This allowed the mycelium to grow
through the printed artefacts and transform the substrate
into the desired bio-composite. Once the growth had
reached the target state, the printed component was
desiccated to reach its final and stable form, stopping
the decomposition process.
Fabrication Strategy
The live pulp was 3D printed using Vormvrij Lutum v4,
which relies on a combination of pressurised air and a
rotating auger to extrude material. A nozzle diameter of
3.5mm was used in combination with a layer height of
1.5mm, which provided a working balance of resolution,
stability, and print speed.
Several factors influence the stability of the print, and the
ability to produce artefacts with the desired geometric
variation. A larger nozzle and consequently greater wall
thickness make for more stable prints, but have the
drawback of lower resolution and decrease in surface to
volume ratio, which reduces the amount of mycelial growth
on the material. Straight vertical walls are prone to both
deformation and collapse. To reduce this, the curvatures
have been maximised and additional interconnections
between walls were introduced.
During desiccation, the material contracts in volume by
approximately 30%. In order to minimise the resulting
distortion, a set of aluminium meshes with vertical
channels were used as print base and cover. These
secure the position of the first and last layers, thereby
constraining the contraction to the Z-axis. Mesh-print
adhesion was improved by the explorative growth of the
mycelium. The meshes allow vertical airflows through the
print, supporting biological growth by ensuring even
moisture levels and the circulation of respiratory gases,
and eventually facilitate rapid and even desiccation.
Design Strategy
In addition to the architectural scale constraints, the
design of the components had to accommodate both the
biological requirements of the fungus and the mechanical
constraints of the printing process. A reaction-diusion
simulation based on the the Gray-Scott model generated
the basis for the form-finding of the fabricated geometries.
The scale of the pattern was derived from the fungus
comb reference. This generative model has been developed
by increasing the feed rate along the vertical axis. The
boundaries of the geometry have been created at the
transition points between the two simulated substances.
Subsequently, the resulting geometry consists of two
(internal and external) interwoven volumes that never
converge, lending itself to functional use in the
architectural outcome. Similar to the structure found in
fungus combs, the model ensures significant vertical
continuity that is beneficial to flows of both air and
structural forces. (Fig. 5)
The curves that constitute the print layers are taken
through a secondary algorithmic transformation which
connects all curves into a single curve on a per-layer basis.
This transformation allows for a continuous extrusion rate
along an uninterrupted toolpath which improves speed,
stability and precision in the print process. This also
ensures that the entire printed component is cohesive and
that additional stabilising cross-bracings are created
without disturbing the continuity and separation of the two
sets of volumes. In order to maintain thin extrusions while
increasing the print height, the design strategy combined
vertical continuity with recurring interconnections, while
strengthening through double curvature.
Three dierent material samples (designated S0, S1, and
S2) were tested for the resulting material properties and
their suitability for architectural application. S0 was printed
substrate with no fungal inoculation, S1 was pulp with the
fungal species Byssomerulius corium, and S2 was pulp
with a Gloeophyllum sp. (Fig. 6). Three tests were carried
out: a bending test to evaluate stiness, a test for dispersion
in water, and a test for water absorption properties. Since
the results from these tests indicated that the Gloeophyllum
pulp composite has the most desirable properties,
additional samples were produced and further scanned to
characterise the distortion of the material during drying
(Fig. 7). This is notable since most other mycelium-based
materials use white rot fungus, while here is was found that
the brown rot fungus, Gloeophyllum, gave the better result.
Mechanical Performance
The bending test showed that the samples with more
extensive hyphae distribution exhibited significantly
higher stiness than the mycelium-free sample and
aorded a slightly higher force before failure (Fig. 8).
The deformation before failure was twice as high for
S0 as S2, with S1 falling in between. The hardness of
the material as perceived when cutting the samples with
a sharp knife was significantly higher with increased
hyphae coverage (S2 > S1 > S0).
Dispersion in Water
The resilience of the material bond when wet was tested
by submerging the samples in water for a period of 10
hours. After this period, the water and samples were
stirred (Fig. 9). The sample without mycelium (S0) quickly
swelled and completely disintegrated upon agitation.
S1 and S2 remained intact during stirring.
A droplet of water was placed on each of the surfaces of
the three samples, and the subsequent absorption was
observed. The droplets on S0 and S1 were quickly
absorbed, while the droplet placed on S2 did not absorb
but maintained its shape, indicating strong hydrophobicity
on the material surface (Fig. 11). The samples’ capacity for
buering water in vapour form was also measured, and
remained equally high in all three samples.
5. Column assemblage:
design to fabrication.
6. Dessic ated printed
sample comparison.
From left: S1 , S0, S2.
7. Detail of the 3D scanne d
prototype. Analysis of
deviation from the
toolpath sent for fabrication,
after printin g, growth and
desiccation. Although there
is considerable distortion,
it is locally dis tributed
throughout t he height of
each module an d therefore
not global, the tolerances
not penalisin g the current
design application.
8. Mechanical performance:
bending test .
7 8
Bio-Integrated Design:
Architecture as Multi-Scalar Interfaces
The printed prototypes and tests conducted on the
resulting bio-composite demonstrate some of the
advantages of the proposed approach. The resulting
components were highly hydrophobic with a retained
capacity of moisture buering, and remained stable even
when exposed to prolonged submersion in water. The
transformation of the material by the fungus resulted in
improved stiness and hardness, and eliminated the
tendency of the samples to delaminate between printed
layers. The surface hardness of the resulting material was
markedly dierent from many other reported mycelium-
based materials. This may be due to the use of a brown rot
fungus instead of white rot, and this strain’s interaction
with the substrate. However, further studies are required
to investigate these relationships.
The ability to fabricate larger scale elements relies on
navigating the requirements in the design space, and
the stability and predictability of the printed components
in the growth and desiccation phases. The robustness
of the process was improved by the inclusion of clay to
the substrate as well as the use of stabilising meshes.
Equally, the component design is of critical significance,
both in terms of enabling the growth of the mycelium
and stabilising the material during and after fabrication.
This resulted in a requirement for a high surface area,
high curvature form.
When engaging with the agency of microorganisms
as well as with highly responsive and interdependent
materials, significant constraints are placed on the
design. These constraints require integration between
the multiple scales of the project, from the microscopic
scale of microbial behaviour, through the material
arrangement at the centimetre scale, all the way to
the component and assembly, and eventually human
scales. Rather than considering these constraints as
limitations, they present an opportunity for responsive
and functional architectures.
The demonstrated components (Fig. 1) assemble into a
column that retains several of the properties that allow
the fungus to thrive: it has a high surface area ratio, the
vertical interstitial spaces allow for convective flow, and
the material exhibits an active interaction with air and
water vapour. These properties remain after the element
is constructed, and can be utilised to aect and modulate
the environment in direct proximity to the column. Rather
than a passive load-carrying element, such a structure
should be considered a part of a building’s vascular
system, mediating and enabling flows that drive an
active modulation of the micro-climates which the
occupants inhabit.
The project demonstrates both the challenges and the
potential of additive fabrication of mycelium composites.
The introduction of fungus improves the properties of the
resulting material in multiple ways, resolving diculties
associated with wood printing through improved water
resistance and increased stiness and hardness.
Compared to previous fungus composites which are
typically fabricated through casting, additive fabrication
can improve the conditions for fungus growth, enabling
faster growth rates and more complete coverage. This can
result in better material performance and more ecient
manufacturing. The process enables complex and
customised form beyond what can be achieved through
casting, opening up new functional potential in the
resulting products.
The biologically active process adds constraints, such as
the need for sterile material processing and the prolonged
wet state. However, it was demonstrated how a
combination of material composition, design integration
and fabrication processes can be used to overcome these
challenges, potentially enabling the use of such materials
in the construction industry. If implemented at large
scales, such a shift could radically reduce the building
industry’s ecological footprint by lessening the need for
extraction of non-renewable minerals and for energy
intense chemical processing, while ensuring
environmentally safe and biodegradable properties.
This research has b een funded by The Crafoor d Foundation and Boverket,
the Swedish Nati onal Board of Housing, B uilding and Planning. We would also
like to extend our grati tude to Eva Frühwald Hansson and Maria Fred riksson at
Lund Universit y for their assistance with th e material testing.
Appels, F.V.W., Camere, S ., Montalti, M., Kara na, E., Jansen, K. M.B.,
Dijksterhuis, J ., Krijgsheld, P. and Wösten, H. A. 2019. ‘Fab rication factors
influencing m echanical, moisture- a nd water-related propertie s of
mycelium-based composites’, M aterials & Design, 161 , pp. 64-71.
Boyce, K. J. and Andrianopoulo s, A. 2006. ‘ Morphogenesis: C ontrol of Cell
Types and Shape’, in Kües U., Fisch er R. (eds), Growth, Dif ferentiation and
Sexualit y vol 1: The Mycota (A Com prehensive Treatise on Fungi as
Experimental Sys tems for Basic and Applied R esearch), Berlin, Heidelberg:
Springer, pp. 3 -20.
Elsacker, E., Vandeloo k, S., Brancart , J., Peeters, E. and D e Laet, L. 2019.
‘Mechanical, physical and chemical characterisation of mycelium-based
composites wi th different types of lig nocellulosic substrates’, PLo S ONE 14(7),
p. e0213954. (doi: 10.1371/jo urnal.pone.0213954)
Gazzè, S. A., Saccon e, L., Smits, M. M., Duran, A. L., Leake, J.R. , Banwart, S.A .,
Ragnarsd ottir, K.V. and McMas ter, T.J. 2013 . ‘Nanoscale Obser vations of
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A., Mel e, T., Block , P. an d Hebel, D. 2018. ‘ Design, Cultivation and A pplication
of Load- Bearing Mycelium Compon ents: The MycoTree at the 2017 Se oul
Biennale of Archi tecture and Urbanism’, International Journal of Sustainable
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Latgé, J. P. and Calde rone, R. 2006. ‘ The Fungal Cell Wall’, in Kües U.,
Fischer R . (eds), Growth, Differentiatio n and Sexuality vol 1: The M ycota
(A Comprehen sive Tre atise on Fungi as Experimental System s for Basic
and Applied Research), Berlin, Heid elberg: Springer, pp. 73 -104.
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Materials in Civil Engineering, 29(7). (doi: 10.1061/(ASCE)MT.1943-
9. Dispersio n in water.
The fungus-free sample
disintegrates co mpletely,
while the two fun gal
composites exhib it minimal
swelling and remain in tact
after stirring .
10. Substr ate development
prototype, h ere without
fungus. T he substrate was
tested for extru dability,
as well as for the desi gn –
material compatibilit y.
11. Hydrophobicity.
From left: S 0, S1, S2.
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... 3D printing of clay is currently limited to small size elements (Cruz 2017, Shi et al. 2019, Ugarte et al. 2020 and requires further investigation. The research presented in this paper is based on references that have already developed techniques for the extrusion of mycelium composites (Soh et al. 2020), material mixtures of mycelium and clay (Rigobello 2017), development of bio-hybrid architectural systems (Colmo and Ayres 2020) and 3D printed material assemblies from cellulose and mycelium (Goidea et al. 2020). The work in this paper extends beyond the existing research by evaluating structural properties of a bio-based and digitally fabricated material, as well as observing material distribution on a microscopic scale. ...
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In this paper we will demonstrate a digital workflow that includes a living material such as mycelium and makes the creation of structural designs possible. Our interdisciplinary research combines digital manufacturing with the use of mycelial growth, which enables fibre connections on a microscopic scale. We developed a structure that uses material informed toolpaths for paste-based extrusion, which are built on the foundation of experiments that compare material properties and growth observations. Subsequently, the tensile strength of 3D printed unfired clay elements was increased by using mycelium as an intelligently oriented fibre reinforcement. Assembling clay-mycelium composites in a living state allows force-transmitting connections within the structure. This composite has exhibited structural properties that open up the possibility of its implementation in the building industry. It allows the design and efficient manufacturing of lightweight ceramic constructions customised to this composite, which would not have been possible using conventional ceramics fabrication methods.
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A critical aspect of human space exploration and eventual settlement is the ability to construct habitats while minimizing payload mass launched from Earth. To respond to this challenge, we have proposed the use of fungal bio-composites for growing extra-terrestrial structures, directly at the destination, significantly lowering the mass of structural materials transported from Earth and minimizing the need for high mass robotic operations and infrastructure preparations. Throughout human history, the construction of habitats has used biologically produced materials, from bone and skins to wood and limestone. Traditionally, the materials are used only post-mortem. Currently, the idea of working with living biological organisms, and the phenomenon of growth itself, is of increasing interest in architecture and space applications. Here, we describe the use of mycelium-based composites as an alternative, biological approach for constructing regenerative and adaptive buildings in extrem environments and extraterrestrial habitats. It is a continuation of our research program initiated under the auspices of the “Myco-architecture Off Planet” NASA NIAC Team. These composites, which are fire-resistant, and insulating, do not consist of volatile organic compounds from petrochemical products and can be used independently or in conjunction with regolith, could employ the living biological growth in a controlled environment, for the process of material fabrication, assembly, maintenance, and repair, providing structures resilient to extra-terrestrial hazards. Here we outline the potential and challenges of using bio-composites for Earth and space applications. We describe how these might be addressed to make this biological approach feasible, providing new, growing materials for designing and building sustainable habitats, both on Earth and for long-duration space missions.
Conference Paper
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Our awareness of the earth's depleting resources has directed focus towards biomaterials, which can be extracted sustainably and biodegraded after use. Current fabrication of biomaterial structures is still restricted in strength and geometry, limiting its use in construction. This paper presents a novel two-phase multi-material fabrication process to create mycelium composite structures of higher porosity and complexity with speculated improvements in strength. First, cellulose pulp inoculated with mycelium is extruded. Then, each layer is filled by a secondary supporting material. This material, in the form of a gravel- and sand-slurry, acts as an inhospitable medium steering mycelial growth, additionally improving aeration to produce stronger structures. After an intermediate growth period, the secondary material, reusable in a closed-loop production model, is removed to reveal the fully-grown mycelium structure. The paper reports on each of the three aspects: the fabrication process, material experimentation of primary and secondary substrates, as well as geometry of varying porosity and performance.
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Mycelium-based composites (MBC) are biodegradable, lightweight, and regenerative materials. Mycelium is the vegetative root of fungi through which they decompose organic matter. The proper treatment of the decomposition process results in MBC. MBC have been used in different industries to substitute common materials to address several challenges such as limited resources and large landfill waste after the lifecycle. One of the industries which started using this material is the architecture, engineering, and construction (AEC) industry. Therefore, scholars have made several efforts to introduce this material to the building industry. The cultivation process of MBC includes multiple parameters that affect the material properties of the outcome. In this paper, as a part of a larger research on defining a framework to use MBC as a structural material in the building industry, we defined different grades of MBC to address various functions. Furthermore, we tested the role of substrate mixture and the cultivation time on the mechanical behavior of the material. Our tests show a direct relationship between the density of the substrate and the mechanical strength. At the same time, there is a reverse relation between the cultivation time and the material mechanical performance.
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The demand for building materials has been constantly increasing, which leads to excessive energy consumption for their provision. The looming environmental consequences have triggered the search for sustainable alternatives. Mycelium, as a rapidly renewable, low-carbon natural material that can withstand compressive forces and has inherent acoustic and fire-resistance properties, could be a potential solution to this problem. However, due to its low tensile, flexural and shear strength, mycelium is not currently widely used commercially in the construction industry. Therefore, this research focuses on improving the structural performance of mycelium composites for interior use through custom robotic additive manufacturing processes that integrate continuous wood fibers into the mycelial matrix as reinforcement. This creates a novel, 100% bio-based, wood-veneer-reinforced mycelium composite. As base materials, Ganoderma lucidum and hemp hurds for mycelium growth and maple veneer for reinforcement were pre-selected for this study. Compression, pull-out, and three-point bending tests comparing the unreinforced samples to the veneer-reinforced samples were performed, revealing improvements on the bending resistance of the reinforced samples. Additionally, the tensile strength of the reinforcement joints was examined and proved to be stronger than the material itself. The paper presents preliminary experiment results showing the effect of veneer reinforcements on increasing bending resistance, discusses the potential benefits of combining wood veneer and mycelium’s distinct material properties, and highlights methods for the design and production of architectural components.
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The current physical goods economy produces materials by extracting finite valuable resources without taking their end of the life and environmental impact into account. Mycelium-based materials offer an alternative fabrication paradigm, based on the growth of materials rather than on extraction. Agricultural residue fibres are inoculated with fungal mycelium, which form an interwoven three-dimensional filamentous network binding the feedstock into a lightweight material. The mycelium-based material is heat-killed after the growing process. In this paper, we investigate the production process, the mechanical, physical and chemical properties of mycelium-based composites made with different types of lignocellulosic reinforcement fibres combined with a white rot fungus, Trametes versicolor. This is the first study reporting the dry density, the Young's modulus, the compressive stiffness, the stress-strain curves, the thermal conductivity, the water absorption rate and a FTIR analyse of mycelium-based composites by making use of a fully disclosed protocol with T. versicolor and five different type of fibres (hemp, flax, flax waste, softwood, straw) and fibre processings (loose, chopped, dust, pre-compressed and tow). The thermal conductivity and water absorption coefficient of the mycelium composites with flax, hemp, and straw have an overall good insulation behaviour in all the aspects compared to conventional materials such as rock wool, glass wool and extruded polystyrene. The conducted tests reveal that the mechanical performance of the mycelium-based composites depends more on the fibre processing (loose, chopped, pre-compressed, and tow), and size than on the chemical composition of the fibres. These experimental results show that mycelium-composites can fulfil the requirements of thermal insulation and have the potential to replace fosile-based composites. The methology used to evaluate the suitability and selection of organic waste-streams proved to be effective for the mycelium-material manufacturing applications.
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MycoTree is a spatial branching structure made out of load-bearing mycelium components. Its geometry was designed using 3D graphic statics, utilising compression-only form to enable the weak material to perform structurally. Using only mycelium and bamboo, the structure represents a provocative vision of how one may move beyond the mining of our construction materials from the earth's crust to their cultivation; how achieving stability through geometry rather than through material strength opens up possibilities to use weaker materials structurally and safely; and ultimately, how newly developed cultivated materials in combination with informed structural design have the potential to propose an alternative to established building materials for a more sustainable construction industry.
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Mycelium-based composites result from the growth of filamentous fungi on organic materials such as agricultural waste streams. These novel biomaterials represent a promising alternative for product design and manufacturing both in terms of sustainable manufacturing processes and circular lifespan. This study shows that their morphology, density, tensile and flexural strength, as well as their moisture- and water-uptake properties can be tuned by varying type of substrate (straw, sawdust, cotton), fungal species (Pleurotus ostreatus vs. Trametes multicolor) and processing technique (no pressing or cold or heat pressing). The fungal species impacts colonization level and the thickness of the air-exposed mycelium called fungal skin. Colonization level and skin thickness as well as the type of substrate determine the stiffness and water resistance of the materials. Moreover, it is shown that heat pressing improves homogeneity, strength and stiffness of the materials shifting their performance from foam-like to cork- and wood-like. Together, these results demonstrate that by changing the fabrication process, differences in performance of mycelium materials can be achieved. This highlights the possibility to produce a range of mycelium-based composites. In fact, it is the first time mycelium composites have been described with natural material properties.
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This paper presents an innovative fungal mycelium-based biofoam. Three different mixing protocols with various substrate materials, including wood pulp, millet grain, wheat bran, a natural fiber, and calcium sulfate, and two packing conditions were tested to produce samples for physical, thermal, and mechanical property characterization. Dry density, thermal conductivity, elastic moduli, Poisson's ratio, and compressive strength were obtained. It was found that densely packed samples following Mixing Protocol II have the highest dry density, elastic moduli, compressive strength, and comparable thermal conductivity, and have met or exceeded like characteristics of the conventional polymeric thermal foams except dry density. The results demonstrate that this biofoam offers great potential for application as an alternative insulation material for building and infrastructure construction, particularly in cold regions, or as light-weight backfill material for geoengineering applications.
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Microorganisms colonizing surfaces can exude a wide range of substances, generally called Extracellular Polymeric Substances (EPS). While EPS has often been visualized as thick mature strata embedding microbes, the initial phases of EPS production, its structure at the micro- and nanoscale and the microbial wall areas involved in its exudation are less known. In this work we use Atomic Force Microscopy to image EPS produced by the fungus Paxillus involutus on phyllosilicate surfaces. Hyphal tips initially deposit EPS which assumes the shape of a “halo” surrounding hyphae. The fusion of adjacent EPS halos is likely responsible for the creation of EPS monolayers covering mineral surfaces. It is also proposed that a specific region of hyphae initiates the formation of mineral channels produced by fungi. The results presented here permit for the first time to propose a model for the initial stages of EPS accumulation in fungi and filamentous microorganisms in general.
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he savannas of southern Africa are dotted with the spectacular mounds of the fungus- growing termites of the genus Macrotermes (Termitidae: Macrotermitinae). These mounds can reach several meters high and represent a colos- sal engineering project for the termites that build them (Fig. 1). The mound is a respiratory device, built to cap- ture wind energy to ventilate the subterranean nest. The need for ventilation is acute. A typical Mac- rotermes nest contains roughly a million workers and a substantially larger biomass of the fungi they cultivate. Collectively, these organisms consume oxygen at rates similar to that of large mammals. By various estimates, a single Macrotermes colony is the metabolic equivalent of a goat or a cow. Macrotermes mounds are also external organs of homeostasis. The composition of the nest at- mosphere is tightly regulated. Typically, oxygen concentrations in the nest are 2% lower than the surrounding air, carbon dioxide concentrations are commensurably higher, and nest humidities are very high. These conditions are maintained throughout the year, and in the face of considerable variation of metabolic demand from the colony. Such stability can only come about if the termites can match ventilation rate with the colony's respi- ration rate. They do this by making the mound a "smart" structure, which means that it must also be a dynamic structure. Soil is continually eroded from the mound and is replaced by soil carried by termites out to the mound surface. Roughly a cubic meter of soil moves through the mound each year in this way. The mound's architecture is therefore shaped by the relative rates and patterns of erosion from, and deposition to, the mound. For the mound to be an organ of homeostasis, these patterns of active soil movement must be coupled to the composition of the nest's atmosphere. For example, excessive ventilation rates would produce patterns of soil transport that reduce the mound's capture of wind energy. Insufficient ventilation would elicit soil transport patterns that enhance the capture of wind energy. How this coupling works is the focus of my re- search, which is underway in the southern African country of Namibia. The work is sponsored by the National Science Foundation and is aided by the National Museum of Namibia and the Namibian Ministry of Agriculture and Rural Development. The latter administers the Omatjenne Research Sta- tion near Otjiwarongo, where the work is based.
Our work explores new design methods and workflows that operate at the intersection of emerging biological technologies and advanced computation and engineering. In 2014 we won a competition to construct a large scale temporary installation to host a series of weekend parties. Our proposal explores the future of architecture by using innovative computational tools to test a new material system at an architectural scale. This paper focuses on the design of a custom computational brick stacking logic that generated the structure’s brick layout within the specific constraints of a new organic material. The resulting digital model was utilized directly to guide the structure’s construction, creating a feedback loop where changes made on site could be fed back into the model to recalculate the layout in real time. While computation and technology play a crucial role in this proposal, the ultimate goal is to show how innovation in materials and methods can lead to a more responsive, intelligent, and sustainable architectural practice.
The search for common host mechanisms that recognize human fungal pathogens as non-self has led to an increased interest in cell wall polysaccharides since they are absent from mammals and at least for some of them, common to all fungal species. Even though the receptors recognizing mannans and beta-1,3-glucans have been extensively studied to date, the epitope of the polysaccharide ligand is often not well defined. In addition, receptors recognizing other cell wall major components such as chitin, alpha-1,3-glucan or galactose polymers remain to be identified. Moreover, the fungal adhesins playing a role in adhesion to host have been only explored in yeasts. Eventhough progresses have been made in the last 10 years, a comprehensive understanding of the interactions between the host membrane receptors and the fungal cell wall components is still lacking.
Morphogenesis: Control of Cell Types and Shape
  • K J Boyce
  • A Andrianopoulos
Boyce, K.J. and Andrianopoulos, A. 2006. 'Morphogenesis: Control of Cell Types and Shape', in Kües U., Fischer R. (eds), Growth, Differentiation and Sexuality vol 1: The Mycota (A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research), Berlin, Heidelberg: Springer, pp. 3-20.