Abstract:
Riverbank erosion is a global problem with signifcant socio-economic impacts. Microbially induced
calcite precipitation (MICP) has recently emerged as a promising technology for improving the
mechanical properties of soils. The present study investigates the potential of selectively enriched
native calcifying bacterial community and its supplementation into the riverbank soil of the
Brahmaputra river for reducing the erodibility of the soil. The ureolytic and calcium carbonate
cementation abilities 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 confrmed the calcite precipitation potential of these communities. The erodibility
of soil treated with native calcifying communities was examined via needle penetration and lab-scale hydraulic fume test. We found a substantial reduction in soil erosion in the biocemented sample with a calcite content of 7.3% and needle penetration index of 16 N/mm. We report the cementation potential of biostimulated ureolytic cultures for minimum intervention to riparian biodiversity for an environmentally conscious alternative to current erosion mitigation practices.
