Sustainable bio‐bricks prepared with synthetic urine enabled by biomineralization reactions.

In this study, mineralization during brick preparation was performed with ureolytic bacterium, Lysinibacillus fusiformis that use urine as a substrate, omitting the heat that is normally required. Artificial urine for reasons of standardization was used to grow the bacterium for bio‐bricks made of clay and cement, but their mineralization was enabled by biological activity instead of by heat. Scanning electron microscopy and energy dispersion X‐ray spectroscopy were conducted to analyse the microstructures formed by L. fusiformis that precipitated various minerals in synthetic urine. The brick specimens were tested for compressive strength that was 59% more than control ones, whereas porosity of bio‐bricks was 13% compared to 22% of control specimens. The minerals formed in the bio‐bricks confirmed as struvite, apatite and calcite by Fourier‐transform infrared spectroscopy and X‐ray diffraction spectra, were responsible for improved strength and reduced porosity. The research provided evidence in utilizing ureolytic bacteria as a mode to mineralize clay in brick production with the use of (artificial) urine as a substrate. [ABSTRACT FROM AUTHOR]