Biocementation Mediated By Stimulated Ureolytic Microbes From Brahmaputra Riverbank For Mitigation of Soil Erosion

Riverbank erosion is a global problem with significant socio-economic impacts. Microbially induced carbonate precipitation (MICP) has recently emerged as a promising technology for improving the mechanical properties of soils. The presented study investigates the potential of native calcifying bacterial communities of the Brahmaputra riverbank for the first time via biostimulation and explores its effect on the mitigation of soil erosion. The ureolytic and calcium carbonate cementation ability of the enriched cultures were investigated with reference to the standard calcifying culture of Sporosarcina pasteurii (ATCC 11859). 16S rRNA analysis revealed Firmicutes to be the most predominant calcifying class with Sporosarcina pasteurii and Pseudogracilibacillus auburnensis as the prevalent strains . The morphological and mineralogical characterization of carbonate crystals confirmed the calcite precipitation potential of these communities. The erosion resistance of soil treated with native calcifying communities was examined via needle penetration and lab-scale flume erosion test. We found a substantial reduction in soil erosion in the biocemented sample with calcite content of 7.3% and needle penetration index of 16 N/mm. We report cementation potential of biostimulated ureolytic cultures for a cost-competitive and environmentally-conscious alternative to current erosion mitigation practices.