Outline:
A recent study has seen scientists create a living construction material employing fungal mycelium. This substance can either undergo natural mineralization or be mineralized through bacterial action, presenting a possibly self-repairing and eco-friendly substitute for traditional concrete.
A recently released study featured in
Cell Reports Physical Science
investigates an innovative method for
sustainable construction
Researchers suggested a biodegradable construction material made from the thread-like structures known as mycelium, which originates from fungal roots.
Neurospora crassa
(N. crassa) can undergo mineralization either through the action of the fungus itself or via the bacterium.
Sporosarcina pasteurii
(S. pasteurii). This engineered living material (ELM) possesses the capability for self-reparation, rendering it an enticing low-emission substitute for traditional concrete.
Background
ELMs represent an expanding category of substances that integrate active cells to facilitate functionalities such as self-repair, autonomous assembly, and photosynthetic processes. Within this group, certain microorganisms have the ability to induce calcite precipitation through microbial-induced calcium carbonate deposition (MICP). This process of biomineralisation serves to reinforce structural integrity more efficiently than conventional concrete manufacturing, doing so under milder conditions with less overall carbon expenditure.
Nonetheless, present biomineralised ELMs encounter significant limitations. They usually have a brief lifespan, generally lasting only a matter of days or weeks, and necessitate meticulously regulated conditions to continue operating effectively. Additionally, current methods provide scant regulation over the inner structure of these materials, which is essential for enhancing their mechanical properties or customising their biological traits.
This research tackles both problems by suggesting a fungus-derived scaffold. The team selected non-pathogenic fungi for this purpose.
N. crassa
For its capacity to carry out urease-mediated microbially induced calcium carbonate precipitation (MICP). The fungus’s mycelium creates a thick, root-like web that provides a bio-structured framework capable of supporting intricate shapes and promoting mineralisation.
Approach
To investigate this idea, the group devised three different mineralization processes: one utilising fungi solely, another combining bacterial mineralization, and a third depending on chemical (non-biological) precipitation.
In the fungal-induced setup,
N. crassa
Was cultivated using two different mediums, FICP-malt and FICP-def, to promote the development of calcium carbonate. Throughout a ten-day span, scientists extracted samples from the liquid medium periodically to track the concentrations of dissolved calcium and urea. Once the experiment concluded, the fungal biomass was gathered, sieved, and dehydrated for subsequent analyses.
To assess bacterial mineralisation (BICP), fungal structures were initially grown in nutrient broth lacking calcium or urea, followed by sterilisation. Subsequently, these autoclaved structures were introduced to bacteria.
S. pasteurii
,enabling the bacterium to start mineralization without being affected by the fungal metabolic processes.
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In the process of abiotic mineralisation (AICP), sterile mycelium was immersed first in a calcium chloride solution and subsequently in a sodium bicarbonate solution. To trigger chemical precipitation of calcium carbonate, the pH was increased using sodium hydroxide.
Each technique was evaluated with colourmetric tests for monitoring calcium and urea concentrations, along with acid digestion to quantify the amount of mineral laid down. The structural and compositional examinations were conducted through scanning electron microscopy (SEM) and X-ray diffraction techniques. Additionally, to assess the functional feasibility, the mineralised matrices were employed to create osteon-like microarchitectures – cylindrical constructs designed to emulate the structure of natural bones.
Findings
Fungal-only scaffolds showed effective mineralisation, with both FICP-malt and FICP-def specimens experiencing a reduction in mass of two to three times more compared to unmineralised controls when subjected to acid digestion. This suggests significant mineral accumulation. Notably, FICP-def scaffolds displayed a 20% larger decrease in mass relative to FICP-malt ones, suggesting enhanced biomineralisation possibly due to increased urease activity or higher biomass content.
When compared, bacterial mineralization proved significantly quicker and more efficient. After merely 24 hours, the BICP scaffolds degraded all the added urea and extracted almost 97% of the calcium from the solution, surpassing the effectiveness of fungus-only systems considerably. To provide some perspective, free-swimming bacteria managed only a 35-39% reduction of these substances within the same period.
Visual proof backed up these conclusions. Scanning electron microscopy (SEM) images showed mineral deposits covering fungal hyphae when present.
S. pasteurii
, while samples lacking calcium showed far less bacterial attachment. These results underscored the effectiveness of bacteria-driven mineralization and the importance of the chemical environment.
Mechanical testing further highlighted performance differences. Nanoindentation revealed that FICP-def scaffolds produced minerals 276 % stiffer than those from the FICP-malt condition. BICP scaffolds delivered even more dramatic improvements—632 % stiffer than FICP-malt and 230 % stiffer than FICP-def. The lower modulus in FICP-malt samples may be due to a softer calcium carbonate phase or organic inclusions during mineral formation.
The bone-like structures developed using these scaffolds exhibited distinct features. Scanning electron microscopy and microcomputed tomography verified the existence of circular patterns made up of minerals. Sandwiched between sand grains within the scaffold, fragmented mineralized mycelium seemed like a lower-density filling, illustrating how this substance combines with particulate elements.
Conclusion
This research provides strong proof that fungal mycelium can act as an effective framework for developing living materials. The methods using both fungi and bacteria showed significant potential for mineralisation without compromising the health of the fungus within these self-forming systems.
Nevertheless, there are some limitations that need addressing. When co-culturing
N. crassa
with
S. pasteurii
was not feasible, indicating that the fungal framework needed to be sterilized prior to initiating bacterial mineralization. Although the group managed to create constructs featuring complex internal designs, their structural characteristics are still under development.
Nevertheless, these initial findings provide crucial foundations for creating eco-friendly substitutes for conventional building components. Through leveraging the self-regulating attributes of fungal mycelium along with the stone-forming abilities of microorganisms, scientists are advancing towards construction materials that are both green and intelligent, adaptable as well as robustly built.
Journal Reference
Viles, E. et al. (2025). Using mycelium as a framework for biomineralized engineered living materials.
Cell Reports Physical Science
,
6
(4). DOI: 10.1016/j.xcrp.2025.102517,
https://www.cell.com/cell-reports-physical-science/fulltext/S2666-3864(25)00116-X
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