scholarly journals New Approach for n-Hexadecane Biodegradation by Sol-Gel Entrapped Bacterial Cells

2018 ◽  
Vol 25 (2) ◽  
pp. 243-253
Author(s):  
Georgi Chernev ◽  
Nelly Christova ◽  
Lyudmila Kabaivanova ◽  
Lilyana Nacheva
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Hybrid Materials ◽  
Immobilized Cells ◽  
Sol Gel ◽  
Cell Immobilization ◽  
Bacterial Cells ◽  
Organic Part ◽  
Force Microscopy ◽  
Biodegradation Process ◽  
Cell Densities

Abstract In this study sol-gel hybrid materials in the system SiO2-chitosan (CS) - polyethylene glycol (PEG), as novel structures with potential application in bioremediation were investigated. The organic components - CS and PEG were used as structural modifiers for functionality improvement. The catabolic activity to n-hexadecane of Pseudomonas aeruginosa BN10 free and immobilized cells was estimated. The cell immobilization technique was employed to evaluate its efficiency on biodegradation and protective effect from high levels of hydrocarbons. The characteristics of obtained hybrid materials were investigated via X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic-force microscopy (AFM) analyses. The obtained results revealed that the organic part in the synthesized hybrids is important for microstructure and defined properties creation. The rate of n-hexadecane mineralization by the bacterial strain was influenced by variation in cell densities applied in the immobilization procedures. Semi-continuous processes with multiple xenobiotic supplies were carried out. The synthesized by the sol-gel method hybrid matrices proved to be suitable carriers for realizing an effective biodegradation process of n-hexadecane by Pseudomonas aeruginosa BN10. Biodegradation of 50 kg/m3 of n-hexadecane was realized by free cells. Significantly greater quantity (150 kg/m3) was mineralized for 15 active cycles by entrapped bacterial cells. Biodegradation process with gradual increase of xenobiotic concentration reaching 30 kg/m3 for 120 h was also accomplished.

Phenol Biodegradation by Fungal Cells Immobilized in Sol-Gel Hybrids

2013 ◽  
Vol 68 (1-2) ◽  
pp. 53-59 ◽  
Author(s):  
Kolishka V. Tsekova ◽  
Georgi E. Chernev ◽  
Alexander E. Hristov ◽  
Lyudmila V. Kabaivanova
Keyword(s):  
Immobilized Cells ◽  
Sol Gel ◽  
Cell System ◽  
Aspergillus Awamori ◽  
Efficient Technology ◽  
Fungal Cell ◽  
Phenol Biodegradation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Repeated Batch

The capability of cells of the fungus Aspergillus awamori, either free or immobilized in hybrid sol-gel material cells, for phenol biodegradation was demonstrated. Phenol was present in the reaction mixture as the sole carbon and energy source, and its decomposition was followed in repeated batch degradation experiments. Atomic force microscopy provided information on the development of self-organizing structures in the materials synthesized by the sol-gel method. Phenol biodegradation was mediated only by the fungal cells, and no absorption by the hybrid matrix was observed. Ten cycles of phenol biodegradation using the immobilized cells system were conducted during which up to 2000 mg l-1 phenol was completely decomposed. Immobilized cells degraded phenol at 8.33 mg h-1, twice as fast as free cells. The good performance of the immobilized fungal cell system is promising for the development of an efficient technology for treating phenol-containing waste waters

Characterization of electrical surface properties of mono- and co-cultures of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus using Kelvin probe force microscopy

RSC Advances ◽  
2014 ◽  
Vol 4 (80) ◽  
pp. 42432-42440 ◽  
Author(s):  
Eric Birkenhauer ◽  
Suresh Neethirajan
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Surface Properties ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Kelvin Probe Force Microscopy ◽  
Bacterial Cells ◽  
Kelvin Probe ◽  
Potential Measurement ◽  
Force Microscopy

Quantitative nanoscale surface potential measurement of individual pathogenic bacterial cells for understanding the adhesion kinetics using Kelvin probe force microscopy.

Synthesis and Characterization of Siloxane-Polyurethane Hybrid Materials

2008 ◽  
Vol 396-398 ◽  
pp. 481-484
Author(s):  
Rodrigo Jiménez-Gallegos ◽  
L. Téllez-Jurado ◽  
Luis M. Rodríguez-Lorenzo ◽  
Julio San Román
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Proton Nuclear Magnetic Resonance ◽  
X Ray Diffraction ◽  
Organic Part ◽  
Sol Gel Process ◽  
Nmr Techniques ◽  
Ft Ir ◽  
Characterization Of Materials

This paper focuses on the preparation of siloxane-polyurethane hybrid materials using a sol-gel method. The global aim of the project is to tailor mechanical properties, degradability rate, bioactivity and biocompatibility to design scaffolds for musculoskeletal applications. A series of seven hybrid materials were synthesized with varying the proportion of polydimethylsiloxane (PDMS), and Polyurethane (PU). The organic part ratios (by weight) employed were (% PDMS:% PU) 30:0, 35:5, 20:10, 15:15, 10:20, 5:25, and 0:30. The organic part was reacted with constant 70 % TEOS to obtain the hybrid materials. A sol-gel process was selected for the synthesis of the hybrids. The characterization of materials was carried out by the fourier-infrared spectroscopy (FT-IR), x-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM) and proton nuclear magnetic resonance (1H-NMR) techniques in order to analyze the structure, microstructure and chemical composition of the hybrid materials. Gelification time depends on the proportion of PU used. When no PU is employed, the gel time is 8 hours but it rises up to 18 days for 30 % of polyurethane. Materials range from opaque to translucent but with a greater fragility for greater amounts of polyurethane. No differences in the bonding of materials could be appreciated.

scholarly journals Hybrid Silica Materials Applied for Fuchsine B Color Removal from Wastewaters

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 863
Author(s):  
Ion Fratilescu ◽  
Zoltán Dudás ◽  
Mihaela Birdeanu ◽  
Camelia Epuran ◽  
Diana Anghel ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Platinum Nanoparticles ◽  
Sol Gel ◽  
Base Catalysis ◽  
Color Removal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Porphyrin Derivatives ◽  
Vis Spectroscopy ◽  
Silica Matrices

Hybrid materials, with applications in fuchsine B color removal from wastewaters, were obtained by in situ incorporation of platinum nanoparticles and/or Pt-porphyrin derivatives into silica matrices. The inorganic silica matrices were synthesized by the sol-gel method, conducted in acid-base catalysis in two steps and further characterized by Nitrogen porosimetry, Small Angle Neutron Scattering (SANS), Scanning electron microscopy, Atomic force microscopy and UV-vis spectroscopy. All of the investigated silica hybrid materials were 100% efficient in removing fuchsine B if concentrations were lower than 1 × 10−5 M. For higher concentrations, the silica matrices containing platinum, either modified with Pt-metalloporphyrin or with platinum nanoparticles (PtNPs), are the most efficient materials for fuchsine B adsorption from wastewaters. It can be concluded that the presence of the platinum facilitates chemical interactions with the dye molecule through its amine functional groups. An excellent performance of 197.28 mg fuchsine B/g adsorbent material, in good agreement with the best values mentioned in literature, was achieved by PtNPs-silica material, capable of removing the dye from solutions of 5 × 10−4 M, even in still conditions.

scholarly journals Silica-carrageenan hybrids used for cell immobilization realizing high-temperature degradation of nitrile substrates

2011 ◽  
Vol 9 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Lyudmila Kabaivanova ◽  
Georgi Chernev ◽  
Isabel Miranda Salvado ◽  
Maria Fernandes
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Cell Immobilization ◽  
Enzyme Reaction ◽  
Batch Experiments ◽  
Good Efficiency ◽  
Biodegradation Process ◽  
Column Bioreactor ◽  
Nitrile Hydrolysis ◽  
Synthesized Materials

AbstractIn this work the application of hybrid materials, containing TEOS as source of SiO2 and k-carrageenan in different percentage, synthesized by the sol-gel method at room temperature was studied. They were used as matrices for entrapment of whole Bacillus sp. UG-5B cells, producers of thermostable nitrilase. The effect of the surface area and size and quantity of pores in the synthesized materials on the enzyme activity was evaluated. The process of biodegradation of different concentrations of toxic, potentially carcinogenic and mutagenic substrates by the obtained biocatalysts was investigated. The enzyme reaction takes place by the nitrilase pathway, catalysing nitrile hydrolysis directly to the corresponding carboxylic acid, forming ammonia. At batch experiments the influence of the substrate concentration of different nitriles was tested and 20 mM concentration was found most suitable. A two-step biodegradation process in a laboratory-scale column bioreactor of o-, m- and p-tolunitrile as a mixture was followed. After operation of the system for nine hours for the mixture of substrates at a flow rate of 45 mL h−1 and at 60°C, the overall conversion realized was above 90%, showing a good efficiency of the investigated process.

scholarly journals Nano- and Macroscale Imaging of Cholesterol Linoleate and Human Beta Defensin 2-Induced Changes in Pseudomonas aeruginosa Biofilms

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1279
Author(s):  
Brent A. Beadell ◽  
Andy Chieng ◽  
Kevin R. Parducho ◽  
Zhipeng Dai ◽  
Sam On Ho ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Cells ◽  
Biofilm Inhibition ◽  
Bacterial Surface ◽  
Force Microscopy ◽  
Novel Treatments ◽  
Atomic Force ◽  
Biofilm Production ◽  
Extracellular Structures ◽  
Induced Changes

The biofilm production of Pseudomonas aeruginosa (PA) is central to establishing chronic infection in the airways in cystic fibrosis. Epithelial cells secrete an array of innate immune factors, including antimicrobial proteins and lipids, such as human beta defensin 2 (HBD2) and cholesteryl lineolate (CL), respectively, to combat colonization by pathogens. We have recently shown that HBD2 inhibits biofilm production by PA, possibly linked to interference with the transport of biofilm precursors. Considering that both HBD2 and CL are increased in airway fluids during infection, we hypothesized that CL synergizes with HBD2 in biofilm inhibition. CL was formulated in phospholipid-based liposomes (CL-PL). As measured by atomic force microscopy of single bacteria, CL-PL alone and in combination with HBD2 significantly increased bacterial surface roughness. Additionally, extracellular structures emanated from untreated bacterial cells, but not from cells treated with CL-PL and HBD2 alone and in combination. Crystal violet staining of the biofilm revealed that CL-PL combined with HBD2 effected a significant decrease of biofilm mass and increased the number of larger biofilm particles consistent with altered cohesion of formed biofilms. These data suggest that CL and HBD2 affect PA biofilm formation at the single cell and community-wide level and that the community-wide effects of CL are enhanced by HBD2. This research may inform future novel treatments for recalcitrant infections in the airways of CF patients.

scholarly journals BACTERIAL DESULFURIZATION OF DIBENZOTHIOPHENE BY PSEUDOMONAS SP. STRAIN KWN5 IMMOBILIZED IN ALGINATE BEADS

2021 ◽  
Vol 83 (2) ◽  
pp. 107-115
Author(s):  
Ida Bagus Wayan Gunam ◽  
Ardiansyah Sitepu ◽  
Nyoman Semadi Antara ◽  
I Gusti Ayu Lani Triani ◽  
I Wayan Arnata ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Immobilized Cells ◽  
Cell Immobilization ◽  
Water System ◽  
Alginate Beads ◽  
Commercial Application ◽  
Sulfur Source ◽  
Bacterial Cells ◽  
Pseudomonas Sp ◽  
Two Phase

Biodelfurization of petroleum has emerged as a potential alternative to the hydrodesulfurization and oxidative desulfurization processes. However, the main obstacle in its commercial application is the efficiency and practicality of using bacterial cells. Pseudomonas sp. strain KWN5 was tested for the ability to use dibenzothiophene (DBT) in n-tetradecane as the sole sulfur source with two phase oil-water system. The biodesulfurization ability of strain KWN5 was evaluated by immobilized cells with dibenzothiophene as substrates. The cells immobilized by entrapping them with sodium alginate (SA) had high DBT biodesulfurization activity and could degrade 100 mg DBT/L in n-tetradecane of 46.76–100%, depended on concentrations of sodium alginate and cells within 24 h at 37oC with shaking at 160 rpm. The combination of SA concentration of 3% (w/v) with bacterial cells OD660 40 (25.52 mg DCW/mL) has an optimal biodesulfurization activity on 100 mg DBT/L in n-tetradecane, which is equal to 71.85% biodesulfurization. The immobilized cells of Pseudomonas sp. strain KWN5 in alginate beads were more efficient for the degradation of DBT and can be reused for five cycles (220 h) without any loss in their activity. The results of this study clearly show the role of the effects of cell immobilization in increasing the process of biodesulfurization.

Development of Sol-Gel Hybrid Materials for Whole Cell Immobilization

2009 ◽  
Vol 3 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Martin Desimone ◽  
Gisela Alvarez ◽  
Maria Foglia ◽  
Luis Diaz
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Cell Immobilization ◽  
Whole Cell

scholarly journals FT-IR Characterization of Antimicrobial Hybrid Materials through Sol-Gel Synthesis

2020 ◽  
Vol 10 (3) ◽  
pp. 1180 ◽  
Author(s):  
Michelina Catauro ◽  
Simona Piccolella ◽  
Cristina Leonelli
Keyword(s):  
Hydrogen Bonds ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Titanium Butoxide ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ft Ir ◽  
Escherichia Coli Bacteria ◽  
Sol Gel Synthesis

Silica/polycaprolactone and titania/polycaprolactone hybrid organic/inorganic amorphous composites were prepared via a sol-gel method starting from a multi-element solution containing tetramethyl orthosilicate (TMOS) or titanium butoxide (TBT), polycaprolactone (PCL), water and methylethylketone (MEK). The molecular structure of the crosslinked network was based on the presence of the hydrogen bonds between organic/inorganic elements as confirmed by Fourier Transform Infra-Red (FT-IR) analysis. In particular, the structure of crosslinked network was realized by hydrogen bonds between the X-OH (X = Si or Ti) group (H donator) in the sol-gel intermediate species and ester groups (H-acceptors) in the repeating units of the polymer. The morphology of the hybrid materials; pore size distribution, elemental homogeneity and surface features, was studied by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and by atomic force microscopy (AFM). The bioactivity of the synthesized hybrid materials was confirmed by observing the formation of a layer of hydroxyapatite (HAP) on the surface of the samples soaked in a simulated body fluid. The antimicrobial behavior of synthetized hybrids was also assessed against Escherichia coli bacteria. In conclusion, the prepared hybrid materials are proposed for use as future bone implants.

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