Use of Fungi as a Means of Producing Concrete-Like Construction Materials
31 October 2022
Concrete is one of the world’s most ubiquitous materials. It has achieved this through its versatility, durability and low cost. However, the manufacture of a key ingredient - Portland cement – contributes 4% of anthropogenic CO2 emissions. Moves to reduce this through partial replacement with other materials, and technologies such as geopolymers, have reached limits imposed by performance requirements, and the often equally-high carbon footprint of geopolymer constituents. Therefore, a need for a low-carbon alternative to Portland cement exists.
Over the last 20 years much research has been conducted into the use of bacteria in ‘self-healing’ concrete [1,2]. Bacterial spores are encapsulated in particles and dispersed in concrete. The particles remain dormant unless ruptured by cracking of the concrete, leading to the release of spores and their germination. The bacteria used are capable of calcite biomineralization, causing precipitation of the mineral in the cracks and repairing damage.
Attempts have been made to take this process a step further and utilise bacteria as a means of fabricating entire construction components, using calcite-biomineralizing bacteria combined with suitable nutrients and minerals which enable them to release carbonate, the calcium arising from the mineral additions . This is a promising approach, although materials produced are currently far from the level of performance required for structural concrete.
Very recently, the possibility of utilising a different group of organisms – fungi – in self-healing concrete has been identified [4,5]. Calcite-precipitating fungi have several advantages over bacteria for this role. Firstly, their filamentous, explorative growth forms have a high surface-to-volume ratio, providing an effective matrix for rapid precipitation. Secondly, they are able to produce calcite through two mechanisms: biomineralization (similarly to bacteria, but at higher efficiency), but also through organo-mineralization (by chitin at cell walls reducing the activation energy of calcite nuclei formation), again permitting faster calcite production. Thirdly, fungi - being organisms commonly encountered in otherwise abiotic environments, such as within rocks  - are suited to reside inside concrete.
This proposed PhD project is built on a depth of preliminary multidisciplinary experimentation between the School of Science and Engineering and the School of Life Sciences, involving academics whose research overlaps each other’s field of expertise, and who have a track record of collaboration [7,8,9,10,11]. It aims to move beyond existing research, and explore whether low carbon footprint, concrete-like construction components can be fabricated using fungi.
The approach adopted will be to initially examine feasibility on small volumes of material to maximise the variables explored. These will include fungal strains (some efficient calcite-forming species are already possessed), ambient conditions, and nutrient/raw material composition and supply. Evaluation of performance of the fungi will be conducted using both mineralogical analyses, characterisation of porosity and strength measurements. The study will also use life-cycle analysis to ensure that any bio-fabrication routes identified are genuinely more sustainable compared with conventional methods.
Should a technically-viable and environmentally-sustainable route to fungal-mediated fabrication be identified, Research Council funding will be sought for a larger project aimed at scaling-up to produce components of a size suitable for construction.
1. Bang, S.S., Galinat, J.K. and Ramakrishnan, V. (2001) Calcite precipitation induced by polyurethane-immobilized Bacillus pasteurii. Enzyme and Microbial Technology 28 404–409.
2. Achal, V., Mukherjee, A., Goyal, S. and Reddy, M.S. (2012) Corrosion prevention of reinforced concrete with microbial calcite precipitation. ACI Materials Journal 109 157–164.
3. Heveran, C.M., Williams, S.L., Qiu, J., Cook, S.M., Cameron, J.C. and Srubar, W.V. (2019) Biomineralization and successive regeneration of engineered living building materials. Matter 2 481–494.
4. Luo, J., Chen, X., Crump, J., Zhou, H., Davies, D.G., Zhou, G., Zhang, N. and Jin, C. (2018) Interactions of fungi with concrete: Significant importance for bio-based self-healing concrete. Construction and Building Materials 164 275-285.
5. Menon, R.R., Luo, J., Chen, X., Zhou, H., Liu, Z., Zhou, G., Zhang, N. and Jin, C. (2019) Screening of fungi for potential application of self-healing concrete. Nature Scientific Reports 9 Article no. 2075.
6. Gadd, G.M. (2017) Fungi, rocks and minerals. Elements 13, 171-176. (invited article for Special Issue: Rock Coatings).
7. Li, Q., Csetenyi,L. and Gadd, G.M. (2014) Biomineralization of metal carbonates by Neurospora crassa. Environmental Science and Technology 48 14409-14416.
8. Li, Q., Csetenyi, L., Paton, G.I. and Gadd, G.M. (2015) CaCO3 and SrCO3 bioprecipitation by fungi isolated from calcareous soil. Environmental Microbiology 17 3082-3097.
9. Gadd, G.M. (2017). Geomicrobiology of the built environment. Nature Microbiology 2, Number 16275, doi:10.1038/nmicrobiol.2016.275 (invited article).
10. Gadd, G.M. and Dyer, T.D. (2017). Bioprotection of the built environment and cultural heritage. Microbial Biotechnology 10, 1152-1156.
11. Dyer, T.D. (2017) Biodeterioration of Concrete. CRC Press, Boca Raton.
How to apply
31 October 2022
- Email Dr Thomas Dyer to:
- send a copy of your CV
- discuss your potential application and any practicalities (e.g. suitable start date).
- After discussion with Dr Dyer, you can apply via our direct application system. Apply for the Doctor of Philosophy (PhD) degree in Civil Engineering