Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these ce...Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these cells enables to prepare magnetic adsorbents that can be easily manipulated in difficult-to-handle samples, such as suspensions, in the presence of external magnetic field. In this review, typical examples of magnetic modifications of microbial cells are presented, as well as their possible applications for the separation of organic xenobiotics and heavy metal ions.展开更多
Various materials have been extensively investigated to mimic the structures and functions of natural enzymes.We describe the discovery of a new catalytic property in the group of biochar-based carbonaceous materials,...Various materials have been extensively investigated to mimic the structures and functions of natural enzymes.We describe the discovery of a new catalytic property in the group of biochar-based carbonaceous materials,which are usually produced during biowaste thermal processing under specific conditions.The tested biochars exhibited peroxidase-like catalytic activ-ity.Biomaterial feedstock,pyrolysis temperature,size of resulting biochar particles or biochar modification(e.g.,magnetic particles deposition)influenced the peroxidase-like activity.Catalytic activity was measured with the chromogenic organic substrates N,N-diethyl-p-phenylenediamine(DPD)or 3,3′,5,5′-tetramethylbenzidine(TMB),in the presence of hydrogen peroxide.Magnetic biochar composite was studied as a complementary material,in which the presence of iron oxide particles enhances catalytic activity and enables smart magnetic separation of catalyst even from complex mixtures.The activity of the selected biochar had an optimum at pH 4 and temperature 32℃;biochar catalyst can be reused ten times without the loss of activity.Using DPD as a substrate,Km values for native wood chip biochar and its magnetic derivative were 220±5μmol L^(−1)and 690±80μmol L^(−1),respectively,while Vmax values were 10.1±0.3μmol L^(−1)min^(−1)and 16.1±0.4μmol L^(−1)min^(−1),respectively.Biochar catalytic activity enabled the decolorization of crystal violet both in the model solution and the fish pond water containing suspended solids and dissolved organic matter.The observed biochar enzyme mimetic activity can thus find interesting applications in environmental technology for the degradation of selected xenobiotics.In general,this property predestines the low-cost biochar to be a perspective supplement or even substitution of common peroxidases in practical applications.展开更多
A simple method for the magnetic modification of various types of powdered agglomerate forming dia- magnetic materials was developed. Magnetic iron oxide particles were prepared from ferrous sulfate by microwave assis...A simple method for the magnetic modification of various types of powdered agglomerate forming dia- magnetic materials was developed. Magnetic iron oxide particles were prepared from ferrous sulfate by microwave assisted synthesis. A suspension of the magnetic particles in water soluble organic solvent （methanol, ethanol, propanol, isopropyl alcohol, or acetone） was mixed with the material to be modified and then completely dried at elevated temperature. The magnetically modified materials were found to be stable in water suspension at least for 2 months.展开更多
Magnetically responsive composite materials have been used in interesting applications in various areas of bioscience, biotechnology, and environmental technology. In this work, a simple method to determine the amount...Magnetically responsive composite materials have been used in interesting applications in various areas of bioscience, biotechnology, and environmental technology. In this work, a simple method to determine the amount of magnetic iron oxide nano- and microparticles attached to magnetically-modified partic- ulate diamagnetic materials has been developed using a commercially available magnetic permeability meter, The procedure is fast and enables dry particulate magnetically modified materials to be analysed without any modification or pretreatment. We show that the magnetic permeability can be measured for materials containing up to 20% magnetic iron oxide, The magnetic permeability measurements are highly reproducible.展开更多
文摘Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these cells enables to prepare magnetic adsorbents that can be easily manipulated in difficult-to-handle samples, such as suspensions, in the presence of external magnetic field. In this review, typical examples of magnetic modifications of microbial cells are presented, as well as their possible applications for the separation of organic xenobiotics and heavy metal ions.
基金This research was supported by the Ministry of the Interior of the Czech Republic(Project No.VI20162019017)by the ERDF projects“New Composite Materials for Environmental Applications”(No.CZ.02.1.01/0.0/0.0/17_048/0007399)“Development of pre-applied research in nanotechnology and biotechnology”(No.CZ.02.1.01/0.0/0.0/17_048/0007323).
文摘Various materials have been extensively investigated to mimic the structures and functions of natural enzymes.We describe the discovery of a new catalytic property in the group of biochar-based carbonaceous materials,which are usually produced during biowaste thermal processing under specific conditions.The tested biochars exhibited peroxidase-like catalytic activ-ity.Biomaterial feedstock,pyrolysis temperature,size of resulting biochar particles or biochar modification(e.g.,magnetic particles deposition)influenced the peroxidase-like activity.Catalytic activity was measured with the chromogenic organic substrates N,N-diethyl-p-phenylenediamine(DPD)or 3,3′,5,5′-tetramethylbenzidine(TMB),in the presence of hydrogen peroxide.Magnetic biochar composite was studied as a complementary material,in which the presence of iron oxide particles enhances catalytic activity and enables smart magnetic separation of catalyst even from complex mixtures.The activity of the selected biochar had an optimum at pH 4 and temperature 32℃;biochar catalyst can be reused ten times without the loss of activity.Using DPD as a substrate,Km values for native wood chip biochar and its magnetic derivative were 220±5μmol L^(−1)and 690±80μmol L^(−1),respectively,while Vmax values were 10.1±0.3μmol L^(−1)min^(−1)and 16.1±0.4μmol L^(−1)min^(−1),respectively.Biochar catalytic activity enabled the decolorization of crystal violet both in the model solution and the fish pond water containing suspended solids and dissolved organic matter.The observed biochar enzyme mimetic activity can thus find interesting applications in environmental technology for the degradation of selected xenobiotics.In general,this property predestines the low-cost biochar to be a perspective supplement or even substitution of common peroxidases in practical applications.
文摘A simple method for the magnetic modification of various types of powdered agglomerate forming dia- magnetic materials was developed. Magnetic iron oxide particles were prepared from ferrous sulfate by microwave assisted synthesis. A suspension of the magnetic particles in water soluble organic solvent （methanol, ethanol, propanol, isopropyl alcohol, or acetone） was mixed with the material to be modified and then completely dried at elevated temperature. The magnetically modified materials were found to be stable in water suspension at least for 2 months.
文摘Magnetically responsive composite materials have been used in interesting applications in various areas of bioscience, biotechnology, and environmental technology. In this work, a simple method to determine the amount of magnetic iron oxide nano- and microparticles attached to magnetically-modified partic- ulate diamagnetic materials has been developed using a commercially available magnetic permeability meter, The procedure is fast and enables dry particulate magnetically modified materials to be analysed without any modification or pretreatment. We show that the magnetic permeability can be measured for materials containing up to 20% magnetic iron oxide, The magnetic permeability measurements are highly reproducible.
