Encapsulation of fungal spores for fungi-mediated self-healing concrete

¹ Research Group of Architectural Engineering, Department of Architectural Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
² Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
³ Research Group of Physical Chemistry and Polymer Science, Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium

^* Corresponding author: aurelie.van.wylick@vub.be

Abstract

Although concrete is a prominent building material in nearly all construction applications, it is also known for its reinforcement corrosion and thus material degradation due to crack formation. These severe durability issues ignited the use of microorganisms to self-heal concrete cracks in a biological way by promoting the precipitation of CaCO₃ on their cell walls. Filamentous fungi have recently emerged as high-potential self-healing agents because of their ability to grow in large mycelial networks providing abundant nucleation sites for CaCO₃ precipitation. Based on the extensive research already conducted on bacteria-based self-healing concrete, protection of the microbial spores in the concrete mix is key to the survival of the microorganism. This research therefore applied a natural encapsulation technique derived from bacteria-based literature on fungal spores. The fungus Trichoderma reesei, already known in the field of self-healing concrete, was used to prepare the capsules. First results showed that the fungus was able to withstand the encapsulation process, yet could not survive when embedded in cement due to its harsh conditions. The possibilities to optimize the procedure are however discussed in the paper and give rise to a broad range of research opportunities.