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The aim of this work was the study of native and galactosidases from Penicillium canescens under denaturing conditions caused by guanidine hydrochloride. Calculation of kinetics and constants of enzymes inactivation was carried out on using experimental kinetic curves of enzyme denaturation. We observed significant differences in the kinetics of inactivation of native and deglycosylated α-galactosidases from P. canescens caused by guanidine hydrochloride. Native enzyme was stable within the selected range of guanidine hydrochloride concentrations (from 0.1 to 3.0 M), retaining no less than 50% of the initial enzyme activity for 3 days. Deglycosylated enzyme preparations were less stable and they lost their activity within 5–30 minutes, when they were treated with guanidine hydrochloride in concentrations above 1 M. Dissociation rate constant of native and deglycosylated forms of the enzyme differed by 10 to 100 folds. It was shown that subunit interactions play a major role in the process of inactivation of the enzyme, and the carbohydrate component is essential for stabilizing of subunit bonds and maintaining conformational stability of the enzyme under denaturing conditions of chemical agents.

One of the important problems of current biotechnology is the usage of enzymes of microbial origin for destruction of poorly soluble compounds and synthesis of new drugs. In recent years a great deal of researchers’ attention has been given to such technologically promising carbohydrases as O-glycosylhydrolases catalyzing the hydrolysis of O-glycoside links in glycosides, oligo- and polysaccharides, glycolipids, and other glycoconjugates. Aim. The review provides data on the position of α-L-rhamnosidases in the modern hierarchical classification of glycosidases and presents data available in the literature on the features of the enzyme structure in various microorganisms. Methods. The publications from the following databases were analyzed: PubMed (https://pubmed. nsbi.nlm.nih.gov/), the Carbohydrate-Active enZYmes (http://www.cazy.org/), the BRENDA Enzyme Database (https://www.brenda-enzymes.org/). Results. Data on the physicochemical, catalytic, and kinetic properties of α-L-rhamnosidases in microorganisms of different taxonomic groups have been systematized. The peculiarities of the substrate specificity of the enzyme depending on the nature of the protein and the growing conditions of the producer are characterized. Conclusions. Functional properties and specificity action of microbial α-L-rhamnosidases suggest their broad-range applicability for food and animal feed processing, as well as obtaining biologically active compounds for the pharmaceutical industry and medicine. [ABSTRACT FROM AUTHOR]

α-L-Rhamnosidase (α-L-rhamnoside-rhamnohydrolase EC 3.2.1.40) showing specificity for terminal α-1,2-, α-1,4- and α-1,6-linked rhamnose residues, which oft en present in glycoconjugates and synthetic glycosides, can be successfully used in biotechnology for the hydrolysis of rhamnopyranoside residues present in some bioflavonoids, glycoproteins, glycolipids, and other glycoconjugates. Previously, we have shown that a significant part of the coordination compounds of various metals act as effectors of the activity of α-L-rhamnosidases. The aim of this investigation was to study the effect of a number of newly synthesized coordination compounds of Ge(IV) and Ba(II), (Co(II), Ni(II), Cu(II), Zn(II) with gluconic acid on the activity of Penicillium tardum and Eupenicillium erubescens α-L-rhamnosidases. Methods. The objects of the study were Penicillium tardum and Eupenicillium erubescens α-L-rhamnosidases. α-L-Rhamnosidase activity was determined by the Davis method using naringin as a substrate. Coordination compounds Ge(IV) and Ba(II), Co(II), Ni(II), Cu(II),and Zn(II) with gluconic acid were used as enzyme activity modifiers. The synthesized complexes correspond to the formulas [M(H2O)6][Ge2(OH)2(C6H8O7)2]⋅nH2O (M = Ba(1), n = 2; Co 2, n = 4; Ni(3), n = 4; Cu(4), n = 4; Zn(5), n = 3). Results. The effect of coordination compounds 1-(5) on the activity of α-L-rhamnosidase in two strains of Penicillium tardum and Eupenicillium erubescens was studied depending on the exposure time and concentration of the effector. It was shown that compound (3) at a concentration of 0.01% (1 h incubation) led to a slight (by 5%) increase in the activity of P. tardum α-L-rhamnosidase. Compound 1 at a concentration of 0.1% led to a decrease in the activity of P. tardum α-L-rhamnosidase by 29% during the first hour, and after 24 h of incubation, a decrease in the inhibitory effect to 15% was noted. Compounds 2 and (4) activated the enzyme by 9-39% at 1h exposure. At a concentration of 0.1% and exposure time of 1 h, compound 1 increased the activity of E. erubescens α-L-rhamnosidase by 80%, while at a decrease in concentration to 0.01%, the activity increased only by 29%. In general, it should be noted that in most cases, an increase in the duration of incubation up to 24 h led to a decrease in the level of activation (or inhibition) and a return to the control values of enzyme activity. Conclusions. The variety of effects of metal coordination compounds on the activity of enzymes, depending on the nature of the cation and the origin of the enzyme, has been established. The involvement of Ba(II) had the greatest activating effect on the activity of E. erubescens α-L-rhamnosidase compared to other metals. [ABSTRACT FROM AUTHOR]

The intensive development of biotechnology in the last decade is largely determined by the growing requirement needs of both medicine and various industries for products of microbial synthesis, including glycosidases, in particular a-L- rhamnosidases. lheir wide use to solve current biological-medical and chemical-technological problems stimulates re- searchers to search for compounds capable of influencing their catalytic activity. Therefore, the purpose of this work was to isolate and purify a-L-rhamnosidase from a new producer of Penicillium restrictum and to investigate multi-ligand germanium-3d-metal complexes with citric acid, phenanthroline, and bipyridine as effectors of its activity. Methods. Ihe object of the study was a-L-rhamnosidase of restrictum. Its purification was carried out by gel filtration and ion exchange chromatography on TSK-gels and Sepharose 6B. The activity of a-L-rhamnosidase was determined us- ing the Davis method with naringin as a substrate. As modifiers of enzyme activity, purposefully synthesized multi- ligand germanium-3d-metal complexes with citric acid, phenanthroline, and bipyridine (INi(bipy)3[Ge(HCit)2] •3H 2 O (1); [Ni(phen)3 ] [Ge(HCit)2]•2H2O (2); [{Cu(bipy)2}2Ge(μ-Cit)2] •12H20 (3); [{Cu(phen)2]2Ge-(Cit)2]•13H2O (4); [Zn(bipy)3][Ge(HCit)2].•12H20 (5); [Zn(phen)3][Ge(HCit)2]•3H2O (6)), were used. Results. From the supernatant of culture fluid of P. restrictum, a-L-rhamnosidase was isolated and purified 23.1 times with a yield of 0.09%. the specific activity of the enzyme was 27.8 units/mL. The enzyme was homogeneous according to gel filtration on Sepharose 6B and had a molecular mass of 50 kDa. It was established that the considered coordination compounds are able to regulate the catalytic activity of a-L-rhamnosidase of P. restrictum. All of them manifest themselves either as a tivators or as inert substances, no inhibition was observed. In addition, the dependence of the degree of enzyme activation by the compounds on their concentration is traced and corresponds to the following series: at a concentration of 0.01% —1 > 6 =-- 5 > 3 >2 =.-- 4 and at a concentration of 0.1 % —1 > 4 > 2 > 5 = 6.3. The catalytic activity is also significantly affect-ed by the time of exposure to the compounds: at a concentration of 0.01% for lh, the activity of the enzyme at the control level was observed for all compounds, whereas at a concentration of 0.1% for 24 h,the activity increased sharply in the presence of compounds 1(300%), 6 (153%), and 2 (134%). The action of the others was at the control level. Conclusions. The obtained data on new complex metal compounds with an activating effect on microbial a-L-rhamnosidases. It has been established that compounds whose structural organization ensures the synergism of the action of all components are the most promising enzyme effectors in a series of coordination compounds of biologically active metals and ligands. [ABSTRACT FROM AUTHOR]

In recent years, the particular interest of researchers is focused on such enzymes as α-L-rhamnosidase and α-galactosidase. These enzymes are considered useful for various applications. α-L Rhamnosidases may be applied for debittering of citrus fruit juices, due to the less bitter taste of the derhamnosylated flavonones, for rhamnose production, and for the determination of the anomeric configuration in polysaccharides, glycosides and glycolipids. These enzymes may enhance wine aroma and flavonoid bioavailability, or assist in the synthesis of pharmaceuticals. α-Galactosidase finds application in many areas. It is widely used in the food industry to improve the quality of soy products by hydrolyzing indigestible galactosides such as raffinose and stachyose, in the processing of raw materials in order to increase the yield of sugar from molasses, and for the biotransformation of human blood erythrocytes of group B (III) in universal donor erythrocytes, as well as in enzyme therapy of some congenital disorders of sphingolipid metabolism. Earlier, as a result of screening microorganisms of different taxonomic groups, we has selected active α-L-rhamnosidase and α-galactosidase producers. One way to increase their activity is using various effector compounds capable of modifying the enzyme activity. The study of the influence of various effectors is one of the priority areas of modern research in biochemistry, biocoordination chemistry, and biotechnology. Recent advantages in the area of biocoordination chemistry revealed high activating properties of double heterometallic mixed-ligand coordination compounds with germanium(IV)/tin(IV) tartaric complex anions and 1,10-phenanthroline/2,2'-bipyridine d-metallic cations. The aim is to estimate the enzyme-effector activity of five similar tartratostannates for the α-L-rhamnosidases of Cryptococcus albidus, Eupenicillium erubescens, and α-galactosidase of Penicillium restrictum. Methods. The activity of α-Galactosidase was determined using p-nitrophenyl-α-D-galactopyranoside («Sigma», USA) as a substrate. The activity of α-L-rhamnosidase was determined using the Davis method. As modifiers of enzyme activity, [Fe(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·2H2O (1), [Co(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·8H2O (2), [Ni(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·2H2O (3), [Cu(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·2H2O (4), and [Zn(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·6H2O (5) were used. Results. The study of the effect of complexes 1--5, which are supramolecular salts consisting of the same tartrate stannate anion (electrophilic agent) and a 1,10-phenanthroline d-metal cation (nucleophilic agent), on the Cryptococcus albidus, Eupenicillium erubescens α-L-rhamnosidases, and Penicillium restrictum α-galactosidase showed that the compounds tested had a different influence on the enzymes' activity. The catalytic activity of α-L-rhamnosidase is significantly influenced by all complexes. The effectiveness of compounds 1--5 for P. restrictum α-galactosidase was less pronounced in comparison with C. albidus and E. erubescens α-L-rhamnosidases. It was mostly at the control level. There was observed a certain pattern in the influence of complexes on α-L-rhamnosidases of Cryptococcus albidus and Eupenicillium erubescens. Compounds 2 and 5 turned out to be the most effective and activated enzymes by 500-900%. Conclusions. Compound 2 [Co(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·8H2O is promising for further use as an effector of the α-L-rhamnosidase activity. [ABSTRACT FROM AUTHOR]

In recent years, cold-adapted enzymes are increasingly used in industrial processes such as the food, textile and beverage industries. Moreover, cold-active enzymes are usually thermolabile and can be inactivated with little heat. This is especially important in reactions where it is necessary to inactivate an enzyme after it has completed its function, while maintaining conditions that allow other enzymes involved in the reaction to function. Among these enzymes, glycosidases play an important role, which are used in medical technological processes, the food industry, biotechnology for the purification and processing of raw materials, as well as in many other areas of human activity. Therefore, the aim of this work was to study the ability of the psychrotolerant bacterium Pseudomonas mandelii U1 to produce glycosidases, in particular a-L-rhamnosidases, and also to investigate their physicochemical properties and substrate specificity. Methods. Glycosidase activities were determined by Romero and Davis methods, protein - by Lowry method. Results. The study of enzymatic activities in the dynamics of growth indicates that already on the third day of cultivation in the supernatant of the culture liquid of P. mandelii U1 α-L-rhamnosidase activity (0.09 U/mg protein) was noted. On the fifth day of cultivation, in addition to α-L-rhamnosidase (0.09 U/mg protein), β-D-glucosidase (0.09 U/mg protein) and α-D-glucosidase (0.09 U/mg protein) activities were identified. On the seventh and ninth days of cultivation, the spectrum of glycosidase activities was wider, except for α-L-rhamnosidase (0.2 and 0.16 U/mg protein, respectively), β-D-glucosidase (0.02 and 0.05 U/mg protein, respectively) and α-D-glucosidase (0.04 and 0.08 U/mg of protein, respectively), α-D-mannosidase (0.025 and 0.025 U/mg protein, respectively), α-D-fucosidase (0.025 and 0.05 U/mg protein, respectively), N-acetyl-β-D-glucosaminidase (0.025 and 0.025 U/mg protein, respectively) and N-acetyl-β-D-galactosaminidase (0.025 and 0.025 U/mg protein, respectively). Since among the studied glycosidase activities, α-L-rhamnosidase was the highest, subsequent studies were aimed at investigating its properties. It was shown that P. mandelii U1 α-L-rhamnosidase has the pH optimum of action at 5.0, and the temperature optimum - at 4 °C. Conclusions. The temperature optimum of P. mandelii U1 α-L-rhamnosidase preparation isolated from moss in Antarctica, Galindez Island, is 4 °C, the optimum pH is 5.0, the enzyme is able to hydrolyze as synthetic substrates p-nitrophenyl-α-L-rhamnopyranoside, p-nitrophenyl-β-D-glucopyranoside, p-nitrophenyl-α-D-glucopyranoside, p-nitrophenyl-α-D-mannopyranoside, and natural substrates - naringin, neohesperidin and rutin, which suggests the possibility of its use in the future in food technologies, in particular in food processing and waste degradation at low temperatures. [ABSTRACT FROM AUTHOR]

α-L-Rhamnosidase [EC 3.2.1.40], enzyme of the hydrolase family has a wide range of applications: in the food industry, for example, in winemaking to improve the quality and aroma of wines, in the production of citrus juices and drinks to remove bitter components (naringin) that improves the quality and nutritional value of these products; in research as an analytical tool for studying the structure of complex carbohydrate-substituted biopolymers. For the successful use of α-L-rhamnosidases in various biotechnological processes, an important aspect is the development of ways to increase their activity. The main factors affecting the growth and metabolism of microorganisms, including the synthesis of enzymes, are the physicochemical conditions of cultivation, the composition of the nutrient medium, the introduction of substances that raise the yield of the enzyme, which is manifested in an increase in its activity. At present, one of the priority directions of modern research is the study of the effect of various effector compounds that are capable to modify the studied enzymatic activity. In this work, which is a continuation of previous studies, a number of mixed-ligand and mixed-ligand-different-metal coordination germanium compounds of with xylaric acid (H5Xylar), 1,10-phenanthroline (Phen), 2,2-bipyridine (bipy) and ions of 3d-metals (Fe2+, Ni2+, Cu2+, Zn2+) were selected as effectors. Study of the effect of these complexes on the activity of Eupenicillium erubescens, Cryptococcus аlbidus and Penicillium tardum α-L-rhamnosidases were the aim of this work. Materials and methods. The objects of research were α-Lrhamnosidases from Eupenicillium erubescens 248, Cryptococcus albidus 1001, and Penicillium tardum IMV F-100074. The α-L-rhamnosidase activity was determined by the Davis method using naringin as a substrate. We used 12 coordination compounds of germanium as modifiers of enzyme activity, the composition and structure of which were established using a combination of physical and chemical research methods: elemental analysis, thermogravimetry, IR spectroscopy and X-ray structural analysis. Structures of seven compounds are deposited in the Cambridge Crystallographic Database. When studying the effect of various compounds on the activity of enzymes, concentrations of 0.1 and 0.01 % were used, exposure times were 0.5 and 24 hours. The test compounds were dissolved in 0.1 % dimethyl sulfoxide. UV-spectra of absorption of native and chemical modified preparations of the enzymes were studied by spectrophotometer-fluorimeter DeNovix DS-11 in the range of 220-340 nm, concentration of the enzyme preparation 1.0 mg of protein/mL. Results. Analysis of the totality of the obtained data (exposure time 24 h, concentration 0.1 %) regarding the effect of the studied compounds on the activity of E. erubescens, C. albidus and P. tardum α-L-rhamnosidases showed that the influence of the studied modifiers for the activity of α-L-rhamnosidases varies depending on the producer strain. Our data allow us to present the following series of modifiers in accordance with an increase in their effect on the activity of enzymes of different producers: E. еrubescens: 12 < 11 < 5 < 3 < 4=10 < 1 < 3 < 8 < 2 < 6 < 7; C. albidus: 10 < 11 < 12 < 9 < 3 < 1=5 < 8=4 < 2 < 6 < 7; P. tardum: 12=2 < 3 < 4 < 11 < 5 < 8 < 1 < 9 < 6 < 10 < 7. Conclusions. The results obtained allow us to conclude that compound (7)(-tris(bipyridine) nickel(II) μ-dihydroxyxylaratogermanate(IV)) is the most effective activator of α-L-rhamnosidases of all three micromycete strains, compound (6)(tris(phenanthroline)nickel(II) μ-dihydroxyxylaratogerman ate(IV)) - on α-L-rhamnosidase from E. erubescens and C. albidus, while compound (10)-(copper(II) μ-dihydroxyxylaratogermanate(IV)-cuprate(II)) - only of P. tardum α-L-rhamnosidase. [ABSTRACT FROM AUTHOR]

The phylogenetic structure of bacteria is not always consistent with the traditional classification scheme based on the phenotypic properties of bacteria. That is one of the problems of modern bacterial taxonomy. In addition, traditional methods to identify bacteria using phenotypic properties have a number of disadvantages. In recent decades, significant progress was achieved in the investigation of microbial world using molecular methods for fast identification. The aim of the study was to clarify the species status of four strains of bacteria isolated from black lichens of the cliffs of Galindez Island in the Antarctic on the basis of phenotypic and genetic analysis. Methods. Morphological and cultural properties of bacteria were studied according to generally accepted microbiological methods. Physiological and biochemical ones were investigated using test systems API Coryne and API 20E (bioMerieux SA, France), according to the manufacturer's instructions. Phylogenetic analysis was performed based on the nucleotide sequences of the 16S rRNA gene. To identify closely related species, a comparative analysis of the nucleotide sequences of 16S rRNA genes was performed using the BLAST software package. The phylogenetic position was determined by constructing trees (dendrograms) to show the position of the studied strains among closely related and typical species (programs ClustalX 2.1, Mega 6.06). The tree was constructed applying ClustalX 2.1 by comparing the nearest neighbors with bootstrap analysis (bootstrap NJ tree) using 1000 bootstrap tests (1000 alternative trees). Then the phylogenetic tree was edited by the program Mega v. 6.00. Results. Based on the results of comparative, phylogenetic and phenotypic analysis, the studied Antarctic strains 180n1, 181n2, 188n2, 190n2 were identified as Pseudomonas fluorescens, Microbacterium foliorum, Sporosarcina aquimarina and Rothia sp., respectively. The coefficient of similarity of 16S rRNA genes of strain 180n1 with such a closely related species from the database P. fluorescens NBRC 14160 was 99.5%; 181n2 with M. foliorum P 333/02 - 99.4%; 188n2 with S. aquimarina SW28 - 99.7%. These strains form common clusters with closely related species on phylogenetic dendrograms. The strain 190n2 can be considered as Rothia sp., since has the remote position from closely related strains in the cluster Rothia and a low percentage of similarity (97.3%) with the species Rothia endophytica YIM 67072. These strains belong to the phyla: Firmicutes, Actinobacteria, Proteobacteria. Conclusions. Phylogenetic and phenotypic analyzes allowed determining the taxonomic position of isolated aerobic chemoorganotrophic microbial strains of the Antarctic. Nucleotide sequences of 16S rRNA genes are deposited in the International GenBank database under numbers HG518622, HG518623, HG518625, HG518626. [ABSTRACT FROM AUTHOR]

The directed search for extremophilic producers in order to obtain hydrolytic enzymes with increased thermal stability has an unconditional practical potential for use in the food and feed industry to improve the quality of the final product. The aim of the work was to study the ability of collection strains of thermophilic fungi to show α-L-rhamnosidase, α-galactosidase, cellulase, β-mannanase, keratinase and caseinolytic activity. Methods. Micromycetes were grown under submerged conditions in test tubes at 42 °C for 8-14 days. Enzymatic activities were studied in the culture liquid supernatant. p-Nitrophenyl-α-D-galactopyranoside, naringin, guar gum galactomannan and Na-carboxymethylcellulose were used as substrates to determine α-galactosidase, α-L-rhamnosidase, β-mannanase and cellulase activities, respectively. Casein and crushed defatted feathers were served as substrates for the determination of proteolytic activity. Results. The enzymatic activity of 50 strains of micromycetes belonging to 17 species was investigated. The studied group showed high activity: 94 % of the strains had at least one, 34 % - two, 26 % - from three to five enzyme activities. The most active keratinase producers were Thielavia terrestris 1920 and 62, Rhizomucor tauricus 1909, Chrysosporium thermophilum 2050, Thermoascus thermophilus 92 and Thermoascus aurantiаcus 2052 (10-26 U/mL). The highest α-L-rhamnosidase activity was observed in T. terrestris 62 (0.35 U/mL), and carboxymethylcellulase activity -in Thermomyces lanuginosus 2046. Six strains showed α-galactosidase (0.05-0.2 U/mL) and four strains - β-mannanase (5-130 U/mL) activity. Conclusions. As a result new strains producing proteolytic and glycolytic enzymes were isolated among thermophilic micromycetes. Soil thermophilic micromycetes can be used as producers of proteolytic and glycolytic enzymes. Of particular interest are the cultures of Acremonium thermophilum 1963, Corynascus thermophilum 2050, C. sepedonium 1899 and 65068, T. thermophilus 1946, which are capable of producing complexes of proteases and glycosidases in the culture liquid. This indicates that these strains are promising for use as destructors in various technologies processing of complex raw materials. [ABSTRACT FROM AUTHOR]

The Antarctic region has significant potential to study the biodiversity of microorganisms and to search for bacterial producers of glycolytic and proteolytic enzymes with new properties. The aim was to study the extracellular glycosidase and proteolytic activity of four bacteria strains isolated from black lichens of the cliffs of Galindez Island in the Antarctic. Methods. Cultures of bacteria were grown in submerged conditions at a temperature of 15 and 26 oC for 48 h. The synthetic and natural substrates such as p-nitrophenyl-glycosides, soluble starch, gelatin, casein and Elastin-Congo red were used to study the enzymatic activity of bacteria. Results. All studied strains showed α-fucosidase activity. Microbacterium foliorum, Sporosarcina aquimarina and Rothia sp. exhibited α-, β-xylosidase, β-glucosidase or β-N-acetylglucosaminidase activity in different ratios. That may indicate the presence of the enzymatic complex of hydrolysis of lichenan and xylan, which are part of polysaccharides of plants and lichens. P. fluorescens and M. foliorum also showed gelatinase activity. The enzymatic activity of bacteria was noted to be higher in the case of cultivating at 15 oC compared to 26 oC. The α-xylosidase of M. foliorum was optimally active at pH 6.0 and 35 oC, the α-xylosidase of Rothia sp. - at pH 6.5 and 35 oC. High level of stability was shown for these enzymes in the pH range from 4.0 to 7.0 and temperature from 15 to 35 оС during 24 h. Conclusions. Antarctic lichens can be a source of bacterial producers of polysaccharide degrading enzymes with new properties and low temperature optimum. The Antarctic cold environment provides the great opportunities to study the adaptive mechanisms of microorganisms and their enzymatic systems in order to develop new biotechnologies. [ABSTRACT FROM AUTHOR]

The aim of the work was to investigate the practical using of α-L-rhamnosidase substrate specificity Cryptococcus albidus. p-Nitrophenyl derivatives of monosaccharides were used to determine the activity and the enzyme specificity. The ability to hydrolyze of natural substrates was evaluated by Davis and high-performance liquid chromatography methods. It was shown that the enzyme exhibited narrow specificity towards the glycon of synthetic substrates and hydrolyzes only p-nitrophenyl-α-Lrhamnopyranoside (Km 4.5 mM) and p-nitrophenyl-α-D-glucopyranoside (Km 10.0 mM). C. albidus α-Lrhamnosidase the most active degrades naringin (Km 0.77 mM), releasing prunin and naringenin. Km for neohesperidin was 3.3 mM. The efficacy of the naringin hydrolysis in grapefruit and pomelo juice was 98 and 94% in 60 min (40 °C, 2 U/ml). As the result of of green tea and orange juice treatment by α-Lrhamnosidase, there was a decrease in the content of rutin, narirutin and hesperidin, indicating that α-1,2-and α-1,6-linked rhamnose could be cleaved from natural flavonoids. The study shows the possibility of citrus juices and green tea treatment by C. albidus α-L-rhamnosidase for the purpose of their taste qualities improvment and obtaining bioavailable flavonoids glucosides. [ABSTRACT FROM AUTHOR]

The aim of the research was a comparative study of the thermal stability of native and modified by various methods α-L rhamnosidases of Eupenicillium erubescens and Cryptococcus albidus for improving the stability of enzymes. Denaturation of native and modified enzymes were performed at 65 0C, pH 5.2. Enzyme activity was determined using p-nitrophenyl-α-L-rhamnopyranoside and naringin. It is found that in the treatment by polyethylenglycol PEG 1500, dextrans 500 and 70 T thermostability of α-L-rhamnosidases tested decreases, while modification with polyethylenglycol 20000 leads to increase thermal stability of the E. erubescens enzyme to 280% and C. albidus to 150%. Comparative study of the thermal stability of the native and modified by cellulose and its derivatives α-L-rhamnosidases of C. albidus and E. erubescens showed that at concentrations cellulose of 5-15 μg/10 μg protein protective effect of polymers on enzymes was investigated was observed. Hydrophobic modifications using succinic anhydride also can slow down the denaturation of α-L-rhamnosidases tested under experimental conditions. These stabilized C. albidus and E. erubescens α-L-rhamnosidases can be used in biotechnological processes. [ABSTRACT FROM AUTHOR]

The aim of research was to investigate the prevalence of complex mannan-degrading enzymes among museum and freshly isolated cultures of micromycetes, actinobacteria and bacteria. It has been shown that the producers of β-mannanases mostly extracted from sources that are rich in plant residues. We detected strains of Penicillium aculeatum, P. tardum and P. rugulosum which produce a complex of β-mannanases and α-galactosidase activity. Also, strains of thermophilic micromycetes species Corynascus sepedonium, Scytalidium thermophilum and Rhizomucor tauricus with high mannanase activity in culture liquid were detected (10 – 130 U/ml). Two strains of P. aculeatum and P. tardum showed β-mannanase, β-mannosidase and α-galactosidase activity. Actinobacteria was shown high potential, 70 % of all tested strains showed mannanase activity; their activity ranged from 2 to 55 U/ml. Among the most active bacterial cultures were representatives of soil microflora: Bacillus circulans, B. subtilis, B. mesentericus, where as among the strains isolated from sea water the active mannanases producers were not found.