Prototyping an additive co-fabrication workflow for architecture: utilizing cyanobacterial MICP in robotic deposition

With the increasing need for architectural sustainability, biodesign offers a new approach to incorporating living organisms in building materials. Bacteria hold a range of biological activities that impact their environment, and which could enable the solidification of inorganic materials; this has already been seen with microbially-induced carbonate precipitation that strengthens bonds between sand particles. This paper describes the novel development of an additive co-fabrication manufacturing process, demonstrating an interdisciplinary approach of architecture and microbiology. Specifically, the activity of a biological deposition (i.e., cyanobacterial calcium carbonate precipitation) and its integration with that of a robotic deposition (i.e., a sand-based biomixture) within an architectural biofabrication workflow. Two bacterial strains were successfully grown in potential sand-based construction materials. Microbiological protocols, such as optical density and fluorescence measurements, were then applied to identify parameters, for harvesting light through photosynthesis and harnessing it to the sedimentation of calcium carbonate. Assessments of the proposed mechanical delivery system and printing properties enabled the outlining of a suitable robotic deposition system for sand-based mixtures. Through examinations of these microbiological and mechanical protocols, this paper outlines design strategies and tradeoffs for an integrated workflow, that corresponds with both the biological (micro) and architectural (macro) scales.