(236a) Sustainable Bioproduction of Structural Materials through Bottom-up Approaches

Structural integrity is a crucial aspect of building materials to ensure the stability of our buildings, roads, and bridges. When exposed to weathering over time, cracks inevitably form and propagate, further threatening structural integrity. Often, such wear - especially in concrete - requires major renovations involving large quantities of new concrete or even complete rebuilding. Large-scale cement production accounts for approximately 8% of global CO₂ emissions, placing a significant burden on both the environment and the economy.

Although concrete has a limited natural ability to self-heal, this capability is typically confined to cracks smaller than 0.1 cm; insufficient to prevent crack propagation in aging structures. Therefore, it is timely and critical to investigate eco-friendly strategies for healing concrete to promote environmental sustainability. Microbially Induced Carbonate Precipitation (MICP) can help fill cracks in concrete, particularly during the early stages of crack formation. However, its effectiveness is limited by complex processing requirements and reduced microbial viability.

To address this issue, we coat the microbes capable of producing calcium carbonate using a simple, solution-based process that leverages the spontaneous self-assembly of naturally derived polyphenols and metal ions. This coating improves microbial viability and supplies an excess of calcium ions, which are essential for calcium carbonate formation. Our results show that the coated microbes actively heal cracks, achieving a substantial reduction in crack width within one month, compared to minimal healing in control samples containing non-viable cells. This work opens new avenues for developing sustainable, low-maintenance, self-healing construction materials with enhanced durability and resilience.