Biocementation, driven by ureolytic bacteria and their biochemical activities, has evolved as a powerful technology for soil stabilization, crack repair, and bioremediation. Ureolytic bacteria play a crucial role in calcium carbonate precipitation through their enzymatic activity, hydrolyzing urea to produce carbonate ions and elevate pH, thus creating favorable conditions for the precipitation of calcium carbonate. While extensive research has explored the ability of ureolytic bacteria isolated from natural environments or culture conditions, bacterial synergy is often unexplored or under-reported. In this study, we isolated bacterial strains from the local eutrophic river canal and evaluated their suitability for precipitating calcium carbonate polymorphs. We identified two distinct bacterial isolates with superior urea degradation ability (conductivity method) using partial 16 S rRNA gene sequencing. Molecular identification revealed that they belong to the Comamonas and Bacillus genera. Urea degradation analysis was performed under diverse pH (6,7 and 8) and temperature (15 °C,20 °C,25 °C and 30 °C) ranges, indicating that their ideal pH is 7 and temperature is 30 °C since 95% of the urea was degraded within 96 h. In addition, we investigated these strains individually and in combination, assessing their microbially induced carbonate precipitation (MICP) in silicate fine sand under low (14 ± 0.6 °C) and ideal temperature 30 °C conditions, aiming to optimize bio-mediated soil enhancement. Results indicated that 30 °C was the ideal temperature, and combining bacteria resulted in significant (p ≤ 0.001) superior carbonate precipitation (14-16%) and permeability (> 10 m/s) in comparison to the average range of individual strains. These findings provide valuable insights into the potential of combining ureolytic bacteria for future MICP research on field applications including soil erosion mitigation, soil stabilization, ground improvement, and heavy metal remediation.
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http://dx.doi.org/10.1007/s11274-024-04038-3 | DOI Listing |
Materials (Basel)
November 2024
Department of Chemistry and Bioengineering, Faculty of Fundamental Sciences, Vilnius Gediminas Technical University (VILNIUSTECH), Saulėtekio al. 11, 10223 Vilnius, Lithuania.
The capacity of biological self-healing concrete (BSHC) to repair cracks relies on the sustained viability and metabolic function of bacteria embedded within the concrete. BSHC structures face significant risk in cold climates due to low temperatures and freeze-thaw (FT) cycles, during which freezing water can generate internal pressure that damages bacterial cells and diminishes their activity. A special feature of this study is the incorporation of bacterial spores within expanded clay aggregates, tested under varying environmental conditions.
View Article and Find Full Text PDFISME J
December 2024
Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, AZ 85287, United States.
Foundational to establishment and recovery of biocrusts is a mutualistic exchange of carbon for nitrogen between pioneer cyanobacteria, including the widespread Microcoleus vaginatus, and heterotrophic diazotrophs in its "cyanosphere". In other such mutualisms, nitrogen is transferred as amino acids or ammonium, preventing losses through specialized structures, cell apposition or intracellularity. Yet, in the biocrust symbiosis relative proximity achieved through chemotaxis optimizes the exchange.
View Article and Find Full Text PDFJ Physiol Pharmacol
October 2024
Institute of Health and Physical Culture, Academy of Applied Sciences, Leszno, Poland.
This study aimed to analyze salivary glucose levels and pH in relation to the intensity of dental caries in healthy, nondiabetic adults. The study was conducted on 61 patients who were assigned to individual groups based on dental examinations and the calculation of the decayed, missing, and filled teeth (DMFT) index. Group 1 (control) included 15 caries-free persons (DMFT=0).
View Article and Find Full Text PDFFront Microbiol
November 2024
Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland.
J Environ Manage
December 2024
Engineering Laboratory for Green Fertilizers, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China. Electronic address:
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