Georgi E. Chernev

Georgi E. Chernev
University of Chemical Technology and Metallurgy | UCTM · Center for Materials Science

About

87
Publications
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289
Citations
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September 2006 - present
University of Chemical Technology and Metallurgy
Position
  • Professor (Associate)

Publications

Publications (87)
Article
Full-text available
In this study sol-gel hybrid materials in the system SiO 2 -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 aerugino...
Article
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Green alga Scenedesmus incrassatulus, strain R 83, was treated by high concentrations of Cu, Cd and Pb added into the nutrition medium. Cd strongly inhibited growth-it was 60% decreased, followed by Pb-about 50% decreased, while the action of Cu appeared to be the less harmful. Cd and Pb impaired cell morphology and development, and worsen the alga...
Article
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The chemical nature of carriers for enzyme immobilization plays an important role for retention of the enzyme activity and stability. Two new materials are synthesized for enzyme immobilization based on trimethoxy silane/cellulose acetate butyrate/poly (amido amine) dendrimers (TMOS/CAB/PAMAM) and methyltriethoxy silane/cellulose acetate propionate...
Article
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Hybrid biosorbents, synthesized by the sol-gel method on the basis of Tetraethylorthosilicate (TEOS) proved to be efficient for the removal of the heavy metal ions from aqueous solutions. The potential use of immobilized in TEOS algal cells of the red microalga Porphyridium cruentum and its products-low and high molecular heteropolysaccharides to r...
Article
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Today, environmental protection is one of the main goals in the strive to preserve the human existence. Development in this area requires invention of new materials, which can reduce the levels of pollution. Hybrid materials are suitable for this purpose, because they combine different desirable properties existing in separate sources into one uniq...
Article
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The sol-gel silica hybrids are materials with application in different fields - pharmacy, medicine, sensors, etc. Concrete self - healing is a new area of applications of this kind of materials. It is connected with filling the cracks and preventing their further destruction as well as providing materials able to form CaCO3 as filler. A combination...
Article
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Application of silica hybrids in concrete field, in particular remediation of the defects is a new area for these materials. It is well known that the concrete variety is the most used and also threatened by destruction material. Formation of defects during the exploitation period is a normal process and remediation via materials, which can block t...
Article
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Bioencapsulation of microbial cells in silica-based matrices has proved to be a good strategy to enhance the biosynthetic capabilities and viability of bioproducers. In the present study, mycelium and pellet cultures of strain Aspergillus oryzae PP were successfully immobilized in sol�gel hybrid matrices composed of tetraethylorthosilicate as an in...
Article
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Hybrid materials, synthesized by the sol-gel method, were used as matrices for immobilization of bacterial cells, producers of the enzyme nitrilase. Different methods were employed for structure investigations of the synthesized hybrids: Fourier transform infrared spectroscopy (FT-IR), BET and atomic force microscopy (AFM). Тhe influence of the str...
Article
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Sol-gel hybrids, containing different quantity of algal polysaccharide were synthesized. The silica-polysacharide hybrids structure was characterized, employing different methods. The results from the BET analyses revealed that introduction of a polysaccharide and formation of a hybrid structure leads to a decrease in the surface area, but to an in...
Article
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Received on 5 th November and finalized on 8 th November 2013 _____________________________________________________________________________ ABSTRACT Sol-gel hybrids containing different quantity of algal polysaccharide were synthesized, characterized and used as matrices for immobilization of bacterial and algal cells. Cell-cell interaction in the...
Article
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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 pro...
Article
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YORDANOVA, M., Y. EVSTATIEVA, G. CHERNEV, S. ILIEVA, R. DENKOVA and D. NIKOLOVA, 2013. Enhancement of xylanase production by sol-gel immobilization of Aspergillus awamori K-1. Bulg. J. Agric. Sci., Supplement 2, 19: 117–119 Technological potential of Aspergillus awamori species is of particular interest in the investigation of new methods for incre...
Article
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In this work Trichoderma viride SL-45, was investigated in new a hybrid matrix by immobilizing method. Vegetative culture of this strain was immobilized in four variations of sol-gel hybrid silica materials, composed of tetraethylorthosilicate as an inorganic precursor, 10 % polyethylene oxide and 5, or 10% carboxymethylcellulose as organic compoun...
Article
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Hybrid materials are innovative and extensively studied, because of the incorporation organic compounds in inorganic network, combining their properties. The properties of the hybrid material can be controlled by variation of the nature and amounts of the components. Recently, the sol-gel synthesis of hybrid materials has been extensively studied d...
Article
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Self-compacting concrete is the new generation composites, characterized with high filling and passing ability, as well as high resistance to segregation. The flexibility and spreading without external vibrations make these materials prefered for producing tense elements. Powder additives and chemical admixtures play an important role for structura...
Article
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Comptes rendus de l'Académie bulgare des Sciences Tome 65, No 7, 2012 BIOLOGIE Microbiologie Abstract Cells of the strain Aspergillus awamori were entrapped in hybrid materials synthesized by the sol-gel method and their capability to degrade phenol was tested. Phenol was used as a sole carbon and energy source and its biodegra-dation was investiga...
Article
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The sol-gel process is a room temperature procedure, which biomolecules can withstand. The hybrids are composites with nanoscaled structure and they, as well as the sol-gel silica materials, can be applied as excellent matrices for cell immobilization. In the present work the research results on sol-gel synthesis and application of hybrid nanocompo...
Conference Paper
Full-text available
Sol-gel processes give new possibilities in the field of chemistry and science. Using the sol-gel method new materials can be synthesized. Hybrid materials formed by the nanoscale inorganic and organic domains are attractive for the purpose of creating new materials compared to the organic or inorganic materials sepa-rately. The hybrid is formed in...
Article
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The purpose of the present work is the sol–gel synthesis, structure characterization and potential application of hybrid biomaterials based on silica precursor (MTES) and natural polymers such as gelatin or pectin. The structure formation in the biomaterials was investigated by XRD, FTIR, BET and AFM. The results showed that all studied hybrid biom...
Article
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As a result of the conducted research in many countries, different types of low temperature clinkers and cements with high sulphate content are developed. In the present article results of a research on the clarification of the range of temperature stability of sulphoferrite calcium and development of a low energy consuming technology for sulphoalu...
Article
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The active puzzolanic additives decrease the participation of clinker in the cement composition by decreasing the calcium hydrate products and improving the chemical, acidic and sulphate stability, and mechanical properties. In this paper the properties of cementcontaining naturalpuzzolanic additives trass and zeolite are studied. The experimental...
Article
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Fungal strains of genus Aspergillus are used for production of industrially important enzymes α-amylase and xylanase and also for the synthesis of heterologous proteins with biocatalytical properties. The influence of different organic compounds used in the composition of hybrid matrices for sol-gel immobilization on the growth behaviour of Aspergi...
Article
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The hybrid materials, synthesized by the sol-gel method, possessing nanoscaled structure and multifunctional properties show various possibilities for application. New biotechnological approaches are being sought to intensify the production of biologically active substances, one of them being the use of immobilized cells. In this work the research...
Article
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This work reports the sol-gel synthesis of silica hybrids. We determined the effect of the type and quantity of silica precursors and organic compounds on the resulting structure, surface area, nanostructure design and size, and potential applications. The structure of the synthesized hybrids was analyzed using FT-IR, XRD, BET-Analysis, SEM, and AF...
Article
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The isolated Antarctic cyanobacterium Synechocystis salina was embedded in silica hybrid matrices. The ability of the cyanobacterium to remove copper (about 7.6 mg.g(-1) biomass) and cadmium (about 9.0 mg.g(-1) biomass) was shown. UV-B treatment of cells prior to their immobilization decreased the percentage of viable cells to 4.5. At the same time...
Article
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The sol-gel synthesis of both hybrid nanomatrices containing tetraethylortosilicate (TEOS) as an inorganic precursor and lactic acid, or sepharose as an organic component was made. Crystal as well as surface morphology of the hybrids were investigated using different methods: X-ray diffraction, infrared spectra, BET-analysis and atomic force micros...
Article
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In 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 an...
Article
Using the sol-gel procedure nano-biomaterials with incorporation of Leptolyngbia foveolarum in the silica matrix were manufactured. The immobilization of algal cells was confirmed with Scanning Electron Microscopy (SEM) investigations and photos. Observation of nano-biomaterials with Atomic Force Microscopy (AFM) shows nanostructure with well-defin...
Article
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The aim of the present work is synthesis of ferroelectric nanomaterials, in the K2O-Nb2O5-SiO2 system via sol- gel method and studying the processes of formation and structure of the synthesized ferroelectric nanomateri- als. The structure of synthesized materials has been studied by means of the following methods: EDS, XRD, FT-IR, SEM and AFM. The...
Article
Full-text available
The main purpose of the present work is the sol-gel synthesis and structure of the hybrid nanomaterials as matrices for two types of cells, producing hydrolytic enzymes. The effect of different percent of algal polysaccharide included in them on the hydrolytic activity of fungal and bacterial cells was investigated. The hybrid sol-gel nanomaterials...
Article
Full-text available
In this work the research results on the sol–gel synthesis and structure of silica nanocomposites, containing carrageenan and their application as carriers for cell immobilization were described. The samples were prepared at room temperature by replacing different quantity of the inorganic precursor with κ-carrageenan. For studying the structure of...
Article
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Alpha-Galactosidase production by the fungus Humicola lutea 120-5 immobilized in a hybrid sol-gel matrix, consisting of tetraethylorthosilicate (TEOS) as a precursor and a mixture of polyethyleneglycol (PEG) and polyvinylalcohol (PVA), was investigated under semicontinuous shake flask cultivation and compared to the enzyme secretion by free cells....
Article
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Recently the sol-gel synthesis of biomaterials has been extensively studied owing to the significant advantages of this method. Room temperature synthesis, metal-organic precursors and organic solvents, as well as the possibility of controlling the chemical conditions of the sol-gel process allow the introduction of organic and bio-organic molecule...
Article
The present paper deals with the influence of the main silica precursors and the type and quantity of organic components (HEMA, PEO and chitin) on the structure of hybrid materials and their applicability for microbial cell immobilization. The sol–gel synthesis and structure formation of gels have been investigated by means of XRD, FT-IR, BET, SEM...
Article
Full-text available
In the present work the algicidal effect of hybrid nanocomposites based on silicon precursor tetraethylortosilicate on the microalgae Chlorella keissleri was investigated. The inorganic-organic hybrid materials have been prepared by substituting part of the inorganic precursor with Ca alginate (5, 10, %). The antibacterial elements Ag, Cu or Zn was...
Article
Full-text available
The main purpose of the present work is the sol-gel synthesis, structure and application of hybrid inorganic-organic hybrids based on different silica precursors and addition of the organic compound sepharose (SP). The structural evolution of the hybrid materials containing different amounts of SP is examined. Formation of silica nanocomposites by...
Article
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The aim of the present work is to produce hybrid inorganic-organic nanostructured sol-gel coatings and to study their structure and corrosion resistance. The coatings were synthesized by sol-gel technology at room temperature using vinyltrimethoxysilane (VTMS) as silicon precursor and methylmethacrylate (MMA) or hydroxyethylmethacrylate (HEMA) as o...
Article
Nanomatrix with incorporated cells of red microalga Dixoniella grisea was prepared and the effect of copper biosorption by free and embedded in the matrix algal cells was studied. The results show satisfactory immobilization of the biocomponent within the sol-gel matrix. ICP-AES (atomic emission spectrometer with inductively coupled plasma) investi...
Article
Aim. The aim of the present study was to carry out a biodegradation process of a mixture of nitriles by biocatalysts obtained by immobilization of thermophilic bacterial cells, producers of nitrilase in a laboratory column bioreactor. Methods. The substrate solution subjected to degradation contained benzonitrile and 4-cyanopyridine in equal quanti...
Article
Full-text available
Sol-gel chemistry has been applied to different research areas. The room temperature synthesis, the metal-organic precursors and organic solvents, as well as the possibility of controlling the chemical conditions of the sol-gel process allow the introduction of organic and bioorganic molecules within the inorganic network. In the present work has...