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1

Tannins and their enzymatic degradation

100%
Pleszczynska M., Szczodrak J.
Biotechnologia
|
2005
|
issue 1
152-165
EN
Tannins as compounds of plant biomass seem to be a very useful raw material for an effective bioconversion. This is due to their abundance and renewability as well as the possibility of producing various chemicals and curative preparations from this source. On the other hand, enzymatic removal of tannins from agricultural feedstocks by tannase is very important for production of digestible feed and food products, clarified beverages and fruit juices or instant tea. This article presents a review of information on tannins and their hydrolysis by microbial tannase. Special attention has been paid to chemical structure of tannins and their negative or positive effects on organisms as well as the production of tannase and its biochemical properties. Most promising prospects for the practical applications of tannase in food, pharmaceutical, cosmetic and leather industries are also discussed.
2

Glucosyltransferases and glucans of mutans Streptococci as virulence factors in the pathogenesis of dental caries

100%
Wiater A., Szczodrak J.
|
2003
|
issue 3
193-206
EN
Mutans streptococci Streptococcus mutans and S. sobrinus play central role in the etiology of human dental caries due to their acidogenic potential and ability to form extracellular water-insoluble and water-soluble glucans in the presence of dietary sucrose. Streptococcal glucans are synthesized by a constitutive group of extracellular and/or cell-associated enzymes showing glucosyltransferase (GTF) activity. Each enzyme has distinctive properties, varying in its requirement for a glucan primer molecule, the proportion of alpha(1-6)- and alpha(1-3)-linkages, the degree of branching it introduces into the glucan, and the total length of glucan chain produced. Moreover, the overall properties of glucan depend on the relative activity of different GTF enzymes, as well as on their interactions, since one GTF may modify the product of another. This review article presents recent trends in the investigations on streptococcal GTFs and glucans. Particular emphasis has been laid on catalytic properties and molecular structure of different GTFs and on the mechanism of synthesis of specific glucans. Furthermore, the role of these enzymes and their products in the pathogenesis of dental caries is also discussed.
3

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

100%
Fiedurek J., Szczodrak J.
Biotechnologia
|
1994
|
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.
4

Production of ethanol from lactose by yeast cells immobilized in open-pore agar

81%
Szczodrak J., Szczodrak Z., Wiater A.
|
|
issue 4
82-93
EN
An open-pore agar matrix has been shown to be suitable for the entrapment of Candida pseudotropicalis whole cells are used in reactions that involve cell growth and gas evolution. The basic conditions for lactose fermentation by immobilized yeast cells i.e. inoculum quantity, pH, temperature and culture time were standardized. It was shown that yeast cells immobilized in the porous carrier could be used repeatedly in the batch fermentation system for seven 36 h cycles without any substantial loss in ethanol yield, and beads of porous agar with entrapped cells did not rupture, even after periods of 18 d of use.
5

Xylan-degrading enzymes ? characterization and application in biotechnology

81%
Tokarzewska-Zadora J., Rogalski J., Szczodrak J.
Biotechnologia
|
2005
|
issue 2
163-182
EN
Xylans as compounds of plant lignocellulosics seem to be a very useful feedstock for an effective utilization in biotechnology. This is due to their abundance and renewability as well as the possibility of producing various chemical by-products, fuels, fodder and food products from this source. On the other hand, an enzymatic removal of xylans from cellulosic pulps and coffee extracts by xylanases is very important for the production of high quality paper and coffee. This review article presents new trends in the investigations on plant xylans and their enzymatic hydrolysis by xylanases of different origin. Special attention has been paid to catalytic properties of different enzymes of xylanolytic complex, to their synergistic interactions, and to the mechanisms of their regulation, as well as molecular structure of the genes encoding particular enzymes. Most promising prospects for the practical applications of xylanases are also discussed.
6

Enzymatic hydrolysis of plant mannans

81%
Prendecka M., Rogalski J., Szczodrak J.
Biotechnologia
|
2005
|
issue 1
61-78
EN
Mannan, as compounds of plant biomass, seem to be a very useful feedstock for the effective utilization in biotechnology. This is due to their abundance and renewability as well as the possibility of producing various chemical by-products, fuels, fodder and food products from this source. On the other hand, the enzymatic removal of mannans from cellulosic pulps and coffee extracts by mannanases is very important for the production of high quality paper and instant coffee. This review article presents new trends in the investigations on plant mannans and their enzymatic hydrolysis by mannanases of different origin. Particular emphasis has been laid on catalytic properties and molecular structure of different enzymes of mannanolytic complex, and on the mechanisms of their regulation and adsorption on wood fibers as well as on genes encoding particular enzymes. Most promising prospects for the practical applications of mannanases are also discussed.
7

alpha (13)-Glucan-degrading enzymes. Part II ? Application in biotechnology

81%
Wiater A., Pleszczynska M., Szczodrak J.
Biotechnologia
|
2006
|
issue 2
221-233
EN
This paper is focused on actual and potential applications of mutanases as enzymatic dental plaque control agents in vitro and in vivo. All studies reported so far have demonstrated that mutanase was effective in preventing dental caries, suppressing the glucan-dependent adherence and the accumulation of microorganisms in dental plaque, and removing biofilms from dentures. In addition to their potential usefulness in dentistry as oral therapeutic agents, alpha-(13)-glucanases might be applicable to investigations of alpha-(13)-glucosidic linkages occurring in microbial cell-wall structures and glucans of certain higher plants. alpha-(13)-Glucanases obtained in a pure form are invaluable tools for studying the chemical structures of carbohydrates. Most promising prospects for the practical applications of alpha-(13)-glucanases in biocontrol of phytopatogenic fungi, as well as in efficient production of fungal protoplasts, are also discussed.
8

alpha-(1->3)-Glucans from cell wall of Laetiporus sulphureus (Bull.:Fr.) Murrill ? isolation, characteristics and application for induction of mutanase synthesis

81%
Wiater A., Pleszczynska M., Szczodrak J., Prochniak K.
Biotechnologia
|
2008
|
issue 2
174-189
EN
Five different methods described in the literature were used for the isolation of alpha-(1->3)-glucans from the cell wall of fruiting bodies of Laetiporus sulphureus (Bull.:Fr.) Murrill, and their comparative analysis was performed. The separated fungal biopolymers were well-characterized in respect of their structure and some physicochemical properties. Structural analyses, i.e., Fourier-transform infra-red (FT-IR) spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy and specific rotation, revealed that the alkali-soluble wall fraction from this basidiomycetous fungus contained about 56% of (1->3)-linked alpha-glucans. Four out of five alpha-(1->3)-glucans isolated by different methods from the mycelium of the polypore fungus L. sulphureus induced higher activity of fungal and bacterial mutanase than those obtained on mutan. Therefore, the alpha-(1->3)-glucans from fruiting bodies of L. sulphureus can be used as a new alternative to streptococcal mutan, which so far has been known as the best inducer of mutanase production
9

alpha (13)-Glucan-degrading enzymes. Part I ? Microbial sources, production, properties, genetics

81%
Wiater A., Pleszczynska M., Szczodrak J.
Biotechnologia
|
2006
|
issue 2
206-220
EN
This paper is the first review article concerning the investigations on alpha-(13)-glucans and their enzymatic hydrolysis by specific alpha-(13)-glucanases. Special attention is paid to microbial sources of these enzymes as well as intensification of their production in cultures, their purification and catalytic properties, and molecular structure of the genes encoding different fungal and bacterial alpha-(13)-glucanases.
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