Development of sustainable bio-brick from Paenibacillus species with enhanced compressive strength and physicochemical properties

The need for sustainable construction material is rapidly increasing in recent past. To cope with this current situation the present study aims to develop bio-brick by inoculating ureolytic bacteria isolated from soil. The developed bio-brick showed 52.98% silt, clay with Plasticity index of 15.02%, Atterberg limits at 32.93% and 17.91% along with the water absorption capacity was found to be 8.52%. The compressive strength of the developed bio-brick increased to 7.15% with 4.49 MPa in comparison with control brick which was 4.19 MPa, thereby demonstrating enhanced mechanical performance compared to conventional fired clay bricks. The developed bio-brick demonstrated enhanced physical properties along with enhanced compressive strength of 7.15%. FTIR and XRD analyses confirmed the presence of silica-based mineral phases contributing to structural enhancement. X-ray diffractogram depicted peaks corresponding to the crystallographic planes of silica with highest diffraction at 26.75 o . Additionally, the EDS analysis demonstrated that the bio-brick contained higher silica (46.83%). The SEM analysis highlighted significant bacterial colonization on the surface of the bio-brick, with clustered microbial formations, which might play important role in enhanced mechanical properties. Statistical analysis confirmed the significance of the observed improvement( p < 0.001). Metabolic profiling via TLC showed major bands at R f values of 0.3, 0.4, 0.6, and 0.7 which were further identified via GC–MS with key metabolites, like Dodecyl acrylate and 2,4-Di-tert-butylphenol. The isolate was identified as Paenibacillus species via 16S rRNA sequencing. The developed bio-brick represents as one of the improved performance relative to conventional bricks with improved durability by balancing the strength and hydrophobic properties with minimal environmental effects. The findings highlight the potential of microbial-mediated bio-bricks as sustainable alternatives with reduced environmental impact, where microbial metabolites contribute to mineralization, binding, and hydrophobicity.