Engineering living building materials for enhanced bacterial viability and mechanical properties

Jishen Qiu; Sherri Cook; Wil V Srubar 3rd; Mija H Hubler; Juliana Artier; Jeffrey C Cameron

doi:10.1016/j.isci.2021.102083

Engineering living building materials for enhanced bacterial viability and mechanical properties

iScience. 2021 Jan 21;24(2):102083. doi: 10.1016/j.isci.2021.102083. eCollection 2021 Feb 19.

Authors

Jishen Qiu¹, Sherri Cook¹, Wil V Srubar 3rd¹, Mija H Hubler¹, Juliana Artier², Jeffrey C Cameron²

Affiliations

¹ Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 1111 Engineering Dr, Boulder, CO 80309, USA.
² Renewable and Sustainable Energy Institute, University of Colorado Boulder, 4001 Discovery Dr, Boulder, CO 80303, USA.

Abstract

Living building materials (LBMs) utilize microorganisms to produce construction materials that exhibit mechanical and biological properties. A hydrogel-based LBM containing bacteria capable of microbially induced calcium carbonate precipitation (MICP) was recently developed. Here, LBM design factors, i.e., gel/sand ratio, inclusion of trehalose, and MICP pathways, are evaluated. The results show that non-saturated LBM (gel/sand = 0.13) and gel-saturated LBM (gel/sand = 0.30) underwent distinct failure modes. The inclusion of trehalose maintains bacterial viability under ambient conditions with low relative humidity, without affecting mechanical properties of the LBM. Comparison of biotic and abiotic LBM shows that MICP efficiency in this material is subject to the pathway selected: the LBM with heterotrophic ureolytic Escherichia coli demonstrated the most mechanical enhancement from the abiotic controls, compared with either ureolytic or CO₂-concentrating mechanisms from Synechococcus. The study shows that tailoring of LBM properties can be accomplished in a manner that considers both LBM microstructure and MICP pathways.

Keywords: Biomaterials; Civil Engineering; Composite Materials; Materials Synthesis.