scholarly journals Urease active bioslurry: a novel soil improvement approach based on microbially induced carbonate precipitation

2016 ◽  
Vol 53 (9) ◽  
pp. 1376-1385 ◽  
Author(s):  
Liang Cheng ◽  
Mohamed A. Shahin
Keyword(s):  
Soil Stabilization ◽  
Soil Improvement ◽  
Carbonate Precipitation ◽  
Bacterial Cells ◽  
Soil Matrix ◽  
Contact Points ◽  
Novel Approach ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Microbially Induced Carbonate Precipitation

This paper presents a novel approach for soil stabilization by microbially induced carbonate precipitation (MICP) using a new urease active catalyzer, named herein as “bioslurry”. The bioslurry, which was produced from the reaction between bacterial culture and 400 mmol/L of CaCl2 and urea, is pre-formed urease active crystals consisting of CaCO3 plus imbedded urease active bacterial cells. By mixing the bioslurry with sand, more than 95% of the bioslurry was retained in the soil matrix as a result of the mechanical trapping mechanism, leading to high resistance to flushing with a low-salinity solution. The retained urease activity of bioslurry was uniformly distributed along the sand matrix, resulting in a rather uniform CaCO3 precipitation. Through repeated treatments with a cementation solution, the unconfined compressive strength of bioslurry treated sand was significantly improved due to the effective CaCO3 precipitation at the contact points of soil grains. Scanning electron microscopy analysis carried out on the bioslurry treated sand revealed that the induced large rhombohedral CaCO3 crystals were localized around the bioslurry spherical fine crystals. The overall outcome of this work is that soil biocementation using the new bioslurry approach is controllable, reproducible, and homogeneous.

Role of B. Licheniformis in bio mineralization of calcium carbonate and its biological applications

2019 ◽  
Vol 1 (6) ◽  
pp. 622-629
Author(s):  
Balakrishnan Arumugam ◽  
Brinda Elangovan
Keyword(s):  
Calcium Carbonate ◽  
Biological Tissues ◽  
Carbonate Precipitation ◽  
X Ray Diffraction ◽  
Calcium Carbonate Precipitation ◽  
Material Technology ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
High Concentrations ◽  
Living Organisms

Bio mineralization is a significant process carried out by living organisms in which minerals are produced through the hardening of biological tissues. Herein, the current study focus on calcium carbonate precipitation, as part of bio mineralization, to be used in applications for CO2 sequestration, material technology, and other fields. A strain B. licheniformis, isolated from marine water, was investigated for its ability to produce urease and induce calcium carbonate precipitation in a metabolic process. It was discovered that B. licheniformis, resisted high concentrations of urea up to 60 g/L. In order to optimize the calcification process of B. licheniformis, the Calcium carbonate precipitation media is used respectively, pH of 10, and culture time of 96 h. Using X-ray diffraction and Scanning Electron Microscopy analysis, the calcium carbonate polymorphs produced by B. licheniformis, were proven to be mainly calcite. The results of this research provide evidence that B. licheniformis can biologically induce calcification and suggest that B. licheniformis may play a potential role in the synthesis of new bio minerals and in bioremediation or bio recovery.

Antibacterial Activity of cLFchimera and its Synergistic Potential with Antibiotics against Some Foodborne Pathogens Bacteria

2020 ◽  
Author(s):  
Sahar Roshanak ◽  
Zana Pirkhezranian ◽  
Fakhri Shahidi ◽  
Mohammad hadi Sekhavati
Keyword(s):  
Foodborne Pathogens ◽  
Synergistic Effects ◽  
Salmonella Typhi ◽  
Synergistic Activity ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
E Coli ◽  
Viable Cells ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Abstract Background: Frequent and unlimited use of antibiotics caused the development of antibiotic resistance by microorganisms. Therefore, there is an argent need to discover novel antibacterial agents or a combination of agents as a safe treatment strategy for various infections. The aim of the present study was to evaluate the synergistic effects of cLFchimera, an antimicrobial peptides (AMPs), and antibiotics on several foodborne bacterial strains. Methods: A checkerboard method was used to determine the synergistic effects of cLFchimera and several antibiotics (Gentamicin, Cefazolin and Ceftazidime) on bacterial strains (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi). Results: The combination of cLFchimera and antibiotics generated a total and partial synergistic interaction for all foodborne bacterial strain used in the present study (FIC= 0.25 to 0.77). In most cases, the effect of peptide and antibiotic synergist on release of cellular content was not different compared to antibiotics when they used alone, but the count of viable cells significantly decreased in combination peptide and antibiotics treatments. Generally, antibacterial dynamics of the combination of peptide and antibiotics showed an increase and stable trend after reaching the peak point for E. coli, P. aeruginosa and S. typhi, respectively. Scanning electron microscopy analysis showed that bacterial cells treated with the combination Gentamycin and cLFchimera were markedly damaged, and most of the outermost layer of the bacterial cells disappeared. Conclusion: Overall, our results may suggest that cLFchimera mediated its synergistic activity independent to antibiotics mode of action by disrupting the cell membrane and intramolecular mechanisms.

scholarly journals An experimental approach to microbial carbonate precipitation in improving the engineering properties of sandy soils

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Baki Bagriacik ◽  
Zahraddeen Kabir Sani ◽  
Fatima Masume Uslu ◽  
Esra Sunduz Yigittekin ◽  
Sadik Dincer
Keyword(s):  
Calcium Carbonate ◽  
Soil Stabilization ◽  
Soil Improvement ◽  
Engineering Properties ◽  
Carbonate Precipitation ◽  
Bacillus Sp ◽  
Calcium Carbonate Precipitation ◽  
Weak Soil ◽  
Direct Shear Tests ◽  
Microbial Carbonate Precipitation

Abstract Purpose Stabilization of weak soil can be achieved through different methods, some of which include jet column, cement stabilization and fly ash stabilization. Unfortunately, the use of the aforementioned methods of soil improvement affects the environment negatively thereby leading to environmental degradation. With the aforesaid impediment in mind, the need for devising methods of weak soil improvement becomes pertinent. Methods Bacillus sp. — a non-pathogenic organism found abundantly in soil — was investigated in this study as a potential agent of soil improvement. The usability of Bacillus sp. in soil improvement was investigated with direct shear tests and permeability tests under optimum conditions in this study. Result Time-dependent study on the effect of the ureolytic bacteria Bacillus sp.-induced calcium carbonate precipitation shows reduction in permeability and increase in the strength of the soil under study. On exhaustion of the available nutrients in the soil, however, the strength of the soil is not negatively impacted. Conclusion Microbially induced calcium precipitation by Bacillus sp. is effective in soil improvement as such it may serve as substitute for conventional soil stabilization techniques. The ability of the bacteria to precipitate calcium carbonate in the soil leads to reduction in the permeability and increase in the shear strength of the soil.

A novel approach for correlative light electron microscopy analysis

2009 ◽  
pp. NA-NA ◽  
Author(s):  
Giuseppe Vicidomini ◽  
Maria C. Gagliani ◽  
Katia Cortese ◽  
Jens Krieger ◽  
Peter Buescher ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Novel Approach ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Material analysis techniques using the ion mill

1996 ◽  
Vol 54 ◽  
pp. 1034-1035
Author(s):  
J. P. Benedict ◽  
R. M. Anderson ◽  
S. J. Klepeis
Keyword(s):  
Polished Surface ◽  
Surface Material ◽  
Analysis Techniques ◽  
Material Analysis ◽  
Optical Inspection ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Argon Ions ◽  
The Impact ◽  
Scanning Electron

Ion mills equipped with flood guns can perform two important functions in material analysis; they can either remove material or deposit material. The ion mill holder shown in Fig. 1 is used to remove material from the polished surface of a sample for further optical inspection or SEM ( Scanning Electron Microscopy ) analysis. The sample is attached to a pohshing stud type SEM mount and placed in the ion mill holder with the polished surface of the sample pointing straight up, as shown in Fig 2. As the holder is rotating in the ion mill, Argon ions from the flood gun are directed down at the top of the sample. The impact of Argon ions against the surface of the sample causes some of the surface material to leave the sample at a material dependent, nonuniform rate. As a result, the polished surface will begin to develop topography during milling as fast sputtering materials leave behind depressions in the polished surface.

Sign in / Sign up

Export Citation Format

Share Document