Biomineralization and Successive Regeneration of Engineered Living Building Materials

Living building materials (LBMs) were engineered that are capable of both biological and structural functions. LBMs were created by inoculating an inert structural sand-hydrogel scaffold with Synechococcus sp. PCC 7002, a photosynthetic cyanobacterium. The scaffold provided structural support for Synechococcus, which toughened the hydrogel matrix via calcium carbonate biomineralization. Temperature and humidity switches were utilized to regulate the metabolic activity of the microorganisms and achieve three successive regenerations of viable LBMs from one parent generation. Microbial viability in LBMs maintained in at least 50% relative humidity for 30 days was 9%–14%, which far exceeded literature values of microorganisms encapsulated in cementitious materials for similar timeframes (0.1%–0.4%). While structural function was maximized at ultradesiccated conditions, prolonged dehydration compromised microbial viability. Despite this tradeoff in biological-structural function, LBMs represent a platform technology that leverages biology to impart novel sensing, responsive, and regenerative multifunctionality to structural materials for the built environment.