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1

Utillity of starch raw materials for biosynthesis of glucose oxidase by Aspegillus niger

100%
Fiedurek J., Szczodrak J.
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issue 3
37-44
EN
Potato starch and its hydrolizates were used to substitute glucose cabon souces to synthesize glucose oxidase (GOD) by free and immobiized on pumice stones A.niger mycellium.The basic conditions for starch hydrolisis, securing the maximal enzyme yields, were optimized.The immobilized A.niger mycelium was able to produce the enzyme at a small loss of its acting (about 28%) during ten 24-h batches.Free mycelium produced about 1.5 times higher GOD activity than the immobilized mycelium on glucose and starch hydrolizates.However,the latter was more stable, reaching faster the maximum of enzyme productivity, and it could be used many times with almost the same efficiency.Thus,the total enzyme yields produced by immunobilized mycelium were much higher than those obtained using the free one.
2

Bioencapsulation of biologically active compounds In matrices obtained by sol-gel metod and its application

81%
Polska K., Fiedurek J., Radzki S.
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2007
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issue 1
77-95
EN
The encapsulation of biomolecules, e.g. enzymes, whole living cells or microorganisms in sol-gel derived monolithic silica, has been widely studied in recent years. Upon encapsulation, biomolecules retain their spectroscopic properties and biological activity. Sol-gel matrices are thermally and chemically stable and can be obtained in a variety of forms, such as optically transparent monoliths, granulates, microparticles or thin films. Sol-gel immobilization is characterized by physical entrapment without chemical modification. Immobilizing substances by physically trapping in individual pore of a matrix permits their molecules to be isolated and stabilized. The advantages of sol-gel encapsulated biologicals might give them applications such as optical and electrochemical sensors, diagnostic devices, catalysts, and even bioartificial organs. While the relatively large biomolecules are immobilized within the silica network, small ions or molecules are transported into the interior of the matrix.
3

Presence, biological role and biotransformation of limonene

81%
Trytek M., Kowalski P., Fiedurek J.
Biotechnologia
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2003
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issue 2
206-217
EN
Monoterpenes, widely distributed in nature, constitute suitable precursor substrates for potential production of valuable natural flavour and fragrance compounds. Among various monoterpenes, limonene is a cheap and readily available starting material, utilized for e.g. biotransformation into more valuable compounds like carvone and alpha-terpineol. This rewiev presents properties, application, and possibilities, as well as trials of biotechnological conversion of limonene using some microorganisms.
4

Monoterpenes ? old compounds, new applications, and biotechnological methods of their production

81%
Trytek M., Paduch R., Fiedurek J., Kandefer-Szerszen M.
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2007
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issue 1
135-155
EN
Monoterpenes, are the largest class of plant secondary metabolites. The review discusses some of their key roles in chemical ecology. Several applications of monoterpenes in flavour and fragrance industry, bioremediation, in prevention and therapy of several inflammatory infection, potential disease-preventive phytochemicals, especially for cancer development, are presented. This review also aims at a potential offered by biocatalysis for the synthesis of valuable natural monoterpenes, highlighting relevant biotransformation of suitable precursors (like pinene, limonene, myrcene) using microorganism and porphyrins. The industrial processes based on biotechnological methods are also discussed in terms of their advantages over classical chemical synthesis and extraction from natural sources.
5

Utility of unconventional oxygenation of culture in gluconic acid fermentation

81%
Fiedurek J., Pielecki J., Gromada A.
Biotechnologia
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1999
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issue 4
179-185
EN
A new apparatus for controlling dissolved oxygen concentration in the culture media was tested. Using the apparatus, the automatic dosing of hydrogen peroxide (decomposed by catalase to oxygen and water) was possible, and a significant increase of dissolved oxygen, gluconic acid (3-fold) and over 5-fold intracellular catalase activity were obtained in comparison with the traditional aeration. It also minimises contamination, lowers the expenses on power consumption of aeration, reduces foaming and, consequently, high cost of antifoam emulsion and bacteriological filters.
6

Porphyrins and phthalocyanines. Part I. Properties and some applications

71%
Trytek M., Makarska M., Polska K., Radzki S., Fiedurek J.
Biotechnologia
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2005
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issue 4
109-127
EN
Nowadays, the chemistry of porphyrins, phthalocyanines and related compounds (usually named as tetrapyrrolic rings) is one of the most interesting and promising subjects of supramolecular chemistry, because of unique photoactive properties of the porphyrin rings and their ability of electron transfer. The possibility of synthesis of tetrapyrroles with countless organic groups substituted to nine reactive centers of porphyrin ring and synthesis of complexes with almost all metal ions and, additionally, easy to modify the molecular structure of such obtained compounds give a chance of using the porphyrins in many different areas of life. In this paper, we present the most significant problems concerning porphyrins and their metal complexes, such as the molecular structures and physicochemical properties. We also show the most interesting applications, including the role of porphyrins as photosensitizers in photolysis of water and in photodynamic therapy (PDT).
7

Porphyrins and phthalocyanines. Part. II. Porphyrins as biomimetic catalysts in organic compounds transformation

71%
Trytek M., Fiedurek J., Polska K., Makarska M., Radzki S.
Biotechnologia
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2005
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issue 4
128-141
EN
The interest in the use of metal porphyrins in biomimetic catalysis has been constantly increasing during the last twenty years, as the enzymology studies were showing the role of this complexes as prosthetic groups of cytochromes P-450, peroxidases and catalases. In particular, a number of research groups have focused their interest on the ability of metal porphyrins to catalyze redox processes on organic compounds under mild conditions, both for converting these compounds into more usuful products and for purifying industrial effluents. The aim of this review is to highlight the efforts of researchers in utilising metalloporphyrins for economically attractive processes. Interesting reactions are allylic hydroxylations of cheap and readily available precursor monoterpenes (like limonene, pinene) for potential production of valuable natural flavour and fragrance compounds, selective oxidation of alkyl chains of the alkanes, regioselective oxidation of cyclic hydrocarbons (eg. cycloheksan), steroids, as well as reduction of the halogenated alkanes.
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