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1

Biotechnological methods of synthesis of biosurfactants Part II. Synthesis of biosurfactants by microorganisms

100%
Bednarski W.
Biotechnologia
|
1999
|
issue 4
24-44
EN
Possibilities of biosurfactants by microorganisms were presented. Examples of microbial biosynthesis of the main groups of biosurfactants were given. Biosurfactants have many potential applications and examples of their utilization were briefly discussed. One of the applications of biosurfactants receiving renewed attention is Microbial Enhanced Oil Recovery (MEOR) and generally use of biosurfactants in pollution removal. Examples of utilization of biosurfactants in these areas were pointed out. Finally, comparison between biosurfactants synthetised by enzymes and microorganisms was presented.
2

Biotechnological methods of synthesis of biosurfactants Part I. Enzymatic synthesis of surfactants

100%
Bednarski W.
Biotechnologia
|
1999
|
issue 4
7-23
EN
Surface active agents (surfactants) are generally amphiphilic substances consisting of hydrophobic and hydrophilic moieties. They have many applications in the food, cosmetics, and pharmaceutical industry, pollution control, etc. Lipases (EC 3.1.1.3; acyloglycerol hydrolase) have many applications and they are able to catalyze synthesis of biosurfactants ie. mono- and diacyloglycerols, carbohydrate esters of fatty acids etc. These products are biodegradable, natural, non-toxic and aceptable by consumers. In this article enzymatic methods of synthesis of biosurfactants are presented.
3

Intensification of carbohydrate changes in lignocellulose wastes during cultivation of fungi

64%
Lewandowska M., Bednarski W.
Biotechnologia
|
1999
|
issue 1
126-143
EN
This work reports the results on bioconversion of two lignocellulose wastes, i.e. wheat waste and faba bean hulls by fungi T. reesei and A. niger. The efficiency of lignocelluloses biodegradation after culturing the fungi was determined on the basis of the reduction of fibre content in the substrates, increase of protein in the preparations obtained, and the yield of protein biosynthesis. The experiments included the determination of the effect of various technological variables on the process intensification, i.e. method of culturing (shake- or surface culture), type of culture (single strains or mixed culture), raw material pre-treatment (physico-chemical or enzymatic treatment), and additional sources of carbon in the medium, inducing the biosynthesis of cellulases. In selected preparations after culturing the fungi, the changes in the composition of dietary fibre (soluble, SDF and insoluble, IDF) and simple sugars in the IDF fraction were analysed in detail.
4

Improvement of beta-galactosidase properties and conditions for its microbial biosynthesis

64%
Bednarski W., Kowalewska-Piontas J.
Biotechnologia
|
2000
|
issue 2
131-141
EN
We present examples of genetic modification of microorganisms capable of beta-galactosidase synthesis. The technological characteristics as termostability, high activity in a low temperature is improved. We also describe intensification of beta-galactosidase secretion to the medium.
5

Lipases - tool in oils and fats biotechnology

64%
Adamczak M., Bednarski W.
Biotechnologia
|
1994
|
issue 4
140-153
EN
Lipases (acylglycerol hydrolases EC 3.1.1.3) comprise a group of enzymes of widespread occurrence.Their biological function is to catalyse the hydrolise of triacylglycerols to give free fatty acids, diacylglycerols, monoglycerols and glycerol.This reaction is riverisble, so that the enzymes also catalyse the formation of acylglycerols.A feature whih differs lipases from other enzymes is their activity on water-insoluble substrates, at oil-water interface. Interest in lipases from different sources, in particular from microorganisms, has markedly incresed in the last decade due to the potential application of lipases in food industry, chemical industry, chemistry, biochemistry and medicine.
6
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Investigations of Phase Transitions in (NH_{4})_{3}H(SO_{4})_{2} Crystal by Means of Mn^{2+} EPR Spectra

64%
Bednarski W., Waplak S.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 6
1185-1192
EN
EPR of Mn^{2+} impurity ion in the (NH_{4})_{3}H(SO_{4})_{2} crystal is studied in the temperature range 80-420 K. It is shown that Mn^{2+} substitutes NH_{4}^{+}(I) ion and is coordinated in deformed oxygen octahedron in which takes two "off-center" positions. Its spin-Hamiltonian parameters and direction cosines of crystal field are determined. The successive EPR line splitting for three phase transitions is discussed.
7

The yield of biosurfactants synthesis by Candida antarctica depending on medium composition and growth conditions

64%
Adamczak M., Bednarski W.
Biotechnologia
|
2000
|
issue 3
181-192
EN
Synthesis of surface active agents by Candida antarctica was considered. Based on chemical structure it was found that biosurfactants synthesized by yeast are glycolipids. Yield of glycolipid synthesis was depended on carbon source (lipids, carbohydrates) in the medium. Synthesis of biosurfactants by C. antarctica was induced by the presence of oils in the medium. During cultivation of C. antarctica in a fermenter with a medium containing soybean oil 45.49 g/dm3 of glycolipids was obtained.
8

Influence of reaction conditions on yield of enzymatic synthesis galactooligosacharides by Penicillium canescens beta-galactosidase

64%
Bednarski W., Kulikowska A.
|
2007
|
issue 2
137-148
EN
The aim of the work was to examine the ability of Penicillium canescens beta-galactosidase to synthesize galactooligosacharides in one or two-phase medium (organic solvents: water). The yield of this process depends mainly on: lactose concentration in water phase, time of reaction, kind of organic solvents and their participation in two-phase medium. The application of ultrafiltration for separation of saccharides from the reaction medium stabilized the yield of galactooligosacharides synthesis.
9
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Electron Paramagnetic Resonance Study of the [(CH_3)_2NH_2]_5Cd_3Cl_{11} Monocrystal Doped with Cu^{2+} ion

51%
Ostrowski A., Bednarski W., Waplak S., Czapla Z.
Acta Physica Polonica A
|
2002
|
vol. 101
|
issue 6
893-899
EN
The paper reports the electron paramagnetic resonance investigation of Cu^{2+} doped [(CH_3)_2NH_2]_5Cd_3Cl_{11} (DMACC) monocrystal. DMACC:Cu^{2+} was studied in the temperature range (6÷293) K. We did not observe any anomalies of spin-Hamiltonian parameters of Cu^{2+} ion corresponding to the temperature anomalies observed in dielectric studies. The electron paramagnetic resonance anomaly recorded at about 40 K results from the subtle changes in bonds angles and Cu-Cl distances and suggests the smooth second order transition.
10
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Microwave X-Band Resonances in Doped Cd₂Nb₂O₇ Monocrystals

51%
Waplak S., Ostrowski A., Wencka M., Bednarski W.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 1
7-11
EN
Cadmium pyroniobiate (CNO) is the ferroic material with unusual diffuse phase diagram which includes both relaxor and nanocluster domains. We present the data for CNO crystals with several admixtures of paramagnetic ions studied on X and S microwave bands at zero-external magnetic field and classical EPR conditions. Our results lead to an assertion of a ferroelectric resonance effect due to "electronic ferroelectricity". The data fit well to the Falicov-Kimball theoretical model applicable to strongly-correlated-electron or mixed-valence systems.
11
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EPR Study of VO^{2+} Center in Fast Proton Conductor K_3H(SO_4)_2

51%
Ostrowski A., Waplak S., Bednarski W.
Acta Physica Polonica A
|
2005
|
vol. 108
|
issue 1
127-135
EN
The pretransitional phenomena of superprotonic phase transition (T_{sp}=471 K) were studied in detail by X-band continuous wave EPR spectra of K_3H(SO_4)_2 crystal doped with VO^{2+} ions. Three kinds of VO^{2+} complexes (magnetically equivalent but structurally non-equivalent) denoted as VO^{2+}(I), VO^{2+}(II), and VO^{2+}(III) were found. "Smearing out" of the superhyperfine structure was observed as a result of interbond proton motion. VO^{2+} impurity replaces K^+ ion and experiences the same average crystal field gradient at T_{sp}=471 K for I- and II-type complexes. The increase in interbond proton frequency hopping above 360 K is a reason of significant line broadening.
12

Technological and nutritious aspects of enzymatic enrichment of milk and it's derivatives in galactooligosaccharides

51%
Demczuk A., Bednarski W., Kowalewska-Piontas J.
Biotechnologia
|
2004
|
issue 3
152-166
EN
Enzymatic hydrolysis of lactose is accompanied by transgalactosylation reaction, thereby producing oligosaccharides. The prebiotic functions of oligosaccharides such as bifidogenic effect and health benefits connected with this effect were described. The mechanism of galactooligosaccharides formation and factors affecting it were also presented. Moreover, the examples of an enzymatic enrichement of milk and it's derivatives in galactooligosaccharides were given.
13
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Pretransition Phenomena in Fast-Proton Conductors

51%
Waplak S., Bednarski W., Ostrowski A.
Acta Physica Polonica A
|
2005
|
vol. 108
|
issue 2
261-270
EN
In this paper we present recent experimental results related to nonlinear crystal field fluctuations and current flow in K_3H(SO_4)_2 fast-proton conductor far below the transition temperature T_g. The results for crystalline and powdered samples are quantitatively explained in the framework of soliton model of charge transport.
14
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EPR Study of Cu^{2+} Doped Fast-Proton Conductor K_3H(SO_4)_2 in the Temperature Range 100-450 K

51%
Ostrowski A., Bednarski W., Waplak S.
Acta Physica Polonica A
|
2003
|
vol. 104
|
issue 6
549-558
EN
The K_3H(SO_4)_2 doped with Cu^{2+} ion was studied in detail by X-band CW EPR. Two kinds of Cu^{2+} complexes (magnetically and structurally nonequivalent) denoted as Cu^{2+}(I) and Cu^{2+}(II) were found. Spin-Hamiltonian parameters, direction cosines, and coordination of Cu^{2+} ion were determined at room temperature. The superhyperfine structure was observed below 250 K as a result of interacting of Cu^{2+} ion with four equivalent protons (I=1/2). Temperature studies of K_3H(SO_4)_2 crystal show that interbond motion as a precursor of superprotonic phase transition occurs at above≈250 K.
15

Trials of stimulation extracellular secretion of beta-galactosidase synthesised by Kluyveromyces fragilis 28

51%
Demczuk A., Kowalewska-Piontas J., Bednarski W.
Biotechnologia
|
2004
|
issue 1
253-259
EN
To induce extracellular secretion of beta-galactosidase synthesised by Kluyveromyces fragilis 28 yeasts, we used: glycin, L-asparagine, L-leucine, dimethylformamide, dimethyl sulfoxide, cetyldimethylethylammonium bromide, penicillin G and glycolipids from Candida antarctica. The highest increase in the secretion of beta-galactosidase was obtained in the yeast culture cultivated in the medium with polypeptone when glycin was used as the secretion inductor. The extracellular activity of beta-galactosidase reached 0.416 A.U./ml, and was 10-fold higher than the beta-galactosidase activity reported in the control group.
16
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Temperature Dependence ofĝ Tensor Anisotropy in (tm-p-PD):Chloranil, Charge Transfer Complex Powders

51%
Grampp G., Sczaniecki P., Żurek S., Bednarski W.
Acta Physica Polonica A
|
2005
|
vol. 108
|
issue 2
317-321
EN
The powders of 2,3,5,6-tetramethyl-p-phenylenediamine:chloranil charge transfer complex were studied by EPR. Numerical pack EPR-NMR was used to simulate and fit the X-band experimental data in the temperature range of 119-298 K. Very good agreement between the experiment and simulations permits to obtain the main values ofĝ matrix and plot their temperature dependence. At 150 K the main g values are g_{xx}=g_{yy}=2.0041 and g_{zz}=2.0015. g splitting factor varies significantly with temperature and shows an anomaly near 200 K. The signal narrows with the temperature increase, which agrees with the earlier observation. Individual component linewidth, used in the simulation is anisotropic and amounts to 0.1-0.8 mT; which is reasonable when compared with those measured earlier for the single crystals of p-phenylenediamine:chloranil, where the narrowest lines are quoted to be 18μT.
17
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Anisotropy Distribution in NiFe/Au/Co/Au Multilayers

45%
Dubowik J., Stobiecki F., Gościańska I., Kociemba M., Bednarski W.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
315-318
EN
We present results of FMR investigations of anisotropy distribution in uncoupled [NiFe/Au/Co/Au]_N structures with alternating in-plane (NiFe) and out-of-plane anisotropies (Co). It is concluded that for NiFe layers anisotropy distribution is negligible and can be increased by "dusting" of NiFe with ultrathin Co layers. The perpendicular anisotropy K_{U}^2 of Co layers depends on Co thickness in a standard way ∝ 1/d_{Co}, and is distributed in a range of ≈10-20% of K_{U}^2 (i.e., ≈ 1.5× 10^6 erg/cm^3).
18
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Magnetic Properties of Epitaxial Fe/(Ga,Mn)As Hybrids

27%
Kalbarczyk K., Dziatkowski K., Szczytko J., Gosk J., Tokarczyk M., Kowalski G., Twardowski A., Bednarski W., Ostrowski A., Waplak S., Martinek J., Liu X., Furdyna J.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 5
873-876
EN
Thin-film structures composed of two kinds of ferromagnetic material - metallic Fe and semiconducting (Ga,Mn)As - were investigated by means of SQUID magnetometry and ferromagnetic resonance spectroscopy. Dependence of remnant magnetic moment on temperature showed unexpected anisotropic features when recorded along two orthogonal in-plane directions. For one of these orientations, the change in sign of the slope of m(T) curve at the Curie point of (Ga,Mn)As was observed, while for the other, an analogous m(T) curve retained monotonic character. Based on the comparison with ferromagnetic resonance data, the apparent non-monotonicity was attributed to the temperature-induced change of balance between the external magnetic field and uniaxial magnetic anisotropy in the plane of Fe layer.
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