Calcium carbonate bioprecipitation mediated by ureolytic bacteria grown in pelletized organic manure medium

Abstract

New sustainable methods utilizing biological processes to mediate the improvement of soil properties have recently emerged. Microbially induced calcite precipitation (MICP) has been demonstrated as a potential sustainable technique for soil improvement and solidification, erosion control and prevention, and remediation of contaminants. This paper describes experiments conducted to demonstrate the efficacy of using pelletised organic manure (POM), supplemented with varying concentrations of yeast extract (20% to 80%, w/v) as a suitable alternative low-cost nutrient source for bacteria cultivation during the MICP soil biocementation process. The evaluation entails using scanning electron microscopy with electron dispersive X-ray spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) analysis for the evaluation of cementation efficiency, relative merits of the mechanisms and biocementation byproduct. The results demonstrated that ureolytic bacteria can be cultivated with POM that contains yeast extract ranging from 4 g/L to 8 g/L and this alternative bacteria cultivation nutrient source produced more crystal formations with less visible pore spaces in biocemented soil. This study reveals that more treatment cycles (bacterial cultures and chemical solution) approach would be required during biocementation to achieve successful crystal shapes to bridge soil particles when using ureolytic bacteria grown in the inexpensive medium supplemented with low yeast extract.

Influence of Enriched Urease Producing Bacteria from Leachate and Restaurant Wastewater on Heavy Metal Removal

“…The visual observation made during the ureolysis-driven reaction time was in line with the findings that had been reported in the literature [16,18,26].…”

“…Two samples were collected from restaurant and leachate wastewater to screen for highly active ureolytic bacteria. Ureolytic bacteria are defined as microorganisms that are capable of secreting enzymes for urea hydrolysis, resulting in biocalcification in the presence of calcium ions [18]. According to [19], consideration or selection of waste sources with suitable conditions (urea as a substrate and an alkaline pH) was crucial so that the desired bacteria could grow and generate urease.…”

“…According to Omoregie et al [18] ureolytic bacteria play two crucial roles in the biomineralization test: first, they produce urease for urea hydrolysis, which then creates an alkaline environment suitable for carbonate precipitation; and second, they provide nucleation sites necessary for the formation of carbonate crystallisation, morphology, and yield of the precipitation. Microbial cementation requires that bacteria be able to travel freely through the water's pore spaces and that there be an adequate amount of particle-particle interaction.…”