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Maria Vrsanska - One of the best experts on this subject based on the ideXlab platform.
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synthesis and hydrolysis of 1 3 β xylosidic linkages by endo 1 4 β xylanase of Cryptococcus albidus
FEBS Journal, 2005Co-Authors: Peter Biely, Maria VrsanskaAbstract:Purified extracellular endo-1,4-β-xylanase (EC 3.2.1.8) of the yeast Cryptococcus albidus was found to catalyze not only the known 1,4-β-transfer, but an alternative transglycosylation reaction leading to the formation of 1,3-β-glycosidic linkages. From a mixture of products of β-xylanase degradation of phenyl β-D-xylopyranoside three xylooligosaccharide fractions, differring chromatographically from the 1,4-β-linked products, were isolated by preparative paper chromatography. Their structure was elucidated by mass spectrometry, 13C-NMR spectroscopy and enzymic hydrolysis by β-xylanase and β-xylosidase. The isomeric xylotriose was identified as 3-O-β-D-xylopyranosyl-4-O-β-D-xylopyranosyl-D-xylose. The fraction of isomeric tetrasaccharides was found to be represented mainly by 4-O-β-D-xylopyranosyl-3-O-β-D-xylopyranosyl-4-O-β-D-xylopyranosyl-D-xylose. The xylooligosaccharides containing one 1,3-β-linkage were also produced on the enzyme treatment of 1,4-β-xylotriose and 1,4-β-xylan. When treated with the enzyme responsible for their synthesis, the isomeric xylooligosaccharides were hydrolyzed at the 1,3-β-linkage, despite the fact the enzyme does not attack 1,3-β-xylan. The results are interpreted in the relation to the characterized four-subsite substrate-binding site of the enzyme.
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positional isomers of thioxylobiose their synthesis and inducing ability for d xylan degrading enzymes in the yeast Cryptococcus albidus
Carbohydrate Research, 1992Co-Authors: Jacques Defaye, Peter Biely, Jeanmichel Guillot, Maria VrsanskaAbstract:Abstract Isomeric S -linked-2-thioxylobiose 10 , 3-thioxylobiose 17 , and 4-thioxylobioise 19 were conveniently prepared by S n 2 displacement of suitable triflylglycoses with the sodium salt of 2,3,4-tri- O -acetyl-1-thio-β- d -glucopyranose, either in N,N -dimethylformamide, or in oxolan in the presence of a sodium complexing agent. Allyl 3,5- O -isopropylidene-2- O -trifluoromethanesulfonyl-β- d -lyxofuranoside was a convenient electrophilic precursor for 10 , which was smoothly obtained after a short sequence of deprotection involving conversion to the 1-propenyl glycoside. 1,2:5,6-Di- O -isopropylidene-3- O -trifluoromethylsulfonyl-α- d -allofuranose and 1,2,3-tri- O -benzoyl-4- O -trifluoromethylsulfonyl-β- l -arabinopyranose were the respective precursors for 17 and 19 . 4-Thioxylobiose has a highly stimulatory effect on the synthesis of enzymes of the xylanolytic system in the yeast Cryptococcus albidus when applied to the cells in the presence of the natural disaccharide inducer (1→4)-β- d -xylobiose.
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hydrolysis of 1 3 and 1 2 β d xylosidic linkages by an endo 1 4 β d xylanase of Cryptococcus albidus
Carbohydrate Research, 1990Co-Authors: Maria Vrsanska, Jan Hirsch, Pavol Kovac, Peter BielyAbstract:Abstract The substrate specificity of an endo-(1→4)-β- d -xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β- d -xylotriosides. In addition to (1→4) linkages, the enzyme could cleave (1→3) and (1→2) linkages adjacent to a (1→4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1→3) linkage that attached a terminal xylopyranosyl group to a (1→4)-linked xylobiosyl moiety. The enzyme did not attack α- d -xylosidic linkages. The rate of cleavage of (1→4) linkages was much higher than those of other linkages at 0.5m m substrate, but the rates were comparable at 20m m substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
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Hydrolysis of (1→3)- and (1→2)-β-d-xylosidic linkages by an endo-(1→4)-β-d-xylanase of Cryptococcus albidus
Carbohydrate Research, 1990Co-Authors: Maria Vrsanska, Jan Hirsch, Pavol Kovac, Peter BielyAbstract:Abstract The substrate specificity of an endo-(1→4)-β- d -xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β- d -xylotriosides. In addition to (1→4) linkages, the enzyme could cleave (1→3) and (1→2) linkages adjacent to a (1→4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1→3) linkage that attached a terminal xylopyranosyl group to a (1→4)-linked xylobiosyl moiety. The enzyme did not attack α- d -xylosidic linkages. The rate of cleavage of (1→4) linkages was much higher than those of other linkages at 0.5m m substrate, but the rates were comparable at 20m m substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
Peter Biely - One of the best experts on this subject based on the ideXlab platform.
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synthesis and hydrolysis of 1 3 β xylosidic linkages by endo 1 4 β xylanase of Cryptococcus albidus
FEBS Journal, 2005Co-Authors: Peter Biely, Maria VrsanskaAbstract:Purified extracellular endo-1,4-β-xylanase (EC 3.2.1.8) of the yeast Cryptococcus albidus was found to catalyze not only the known 1,4-β-transfer, but an alternative transglycosylation reaction leading to the formation of 1,3-β-glycosidic linkages. From a mixture of products of β-xylanase degradation of phenyl β-D-xylopyranoside three xylooligosaccharide fractions, differring chromatographically from the 1,4-β-linked products, were isolated by preparative paper chromatography. Their structure was elucidated by mass spectrometry, 13C-NMR spectroscopy and enzymic hydrolysis by β-xylanase and β-xylosidase. The isomeric xylotriose was identified as 3-O-β-D-xylopyranosyl-4-O-β-D-xylopyranosyl-D-xylose. The fraction of isomeric tetrasaccharides was found to be represented mainly by 4-O-β-D-xylopyranosyl-3-O-β-D-xylopyranosyl-4-O-β-D-xylopyranosyl-D-xylose. The xylooligosaccharides containing one 1,3-β-linkage were also produced on the enzyme treatment of 1,4-β-xylotriose and 1,4-β-xylan. When treated with the enzyme responsible for their synthesis, the isomeric xylooligosaccharides were hydrolyzed at the 1,3-β-linkage, despite the fact the enzyme does not attack 1,3-β-xylan. The results are interpreted in the relation to the characterized four-subsite substrate-binding site of the enzyme.
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positional isomers of thioxylobiose their synthesis and inducing ability for d xylan degrading enzymes in the yeast Cryptococcus albidus
Carbohydrate Research, 1992Co-Authors: Jacques Defaye, Peter Biely, Jeanmichel Guillot, Maria VrsanskaAbstract:Abstract Isomeric S -linked-2-thioxylobiose 10 , 3-thioxylobiose 17 , and 4-thioxylobioise 19 were conveniently prepared by S n 2 displacement of suitable triflylglycoses with the sodium salt of 2,3,4-tri- O -acetyl-1-thio-β- d -glucopyranose, either in N,N -dimethylformamide, or in oxolan in the presence of a sodium complexing agent. Allyl 3,5- O -isopropylidene-2- O -trifluoromethanesulfonyl-β- d -lyxofuranoside was a convenient electrophilic precursor for 10 , which was smoothly obtained after a short sequence of deprotection involving conversion to the 1-propenyl glycoside. 1,2:5,6-Di- O -isopropylidene-3- O -trifluoromethylsulfonyl-α- d -allofuranose and 1,2,3-tri- O -benzoyl-4- O -trifluoromethylsulfonyl-β- l -arabinopyranose were the respective precursors for 17 and 19 . 4-Thioxylobiose has a highly stimulatory effect on the synthesis of enzymes of the xylanolytic system in the yeast Cryptococcus albidus when applied to the cells in the presence of the natural disaccharide inducer (1→4)-β- d -xylobiose.
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hydrolysis of 1 3 and 1 2 β d xylosidic linkages by an endo 1 4 β d xylanase of Cryptococcus albidus
Carbohydrate Research, 1990Co-Authors: Maria Vrsanska, Jan Hirsch, Pavol Kovac, Peter BielyAbstract:Abstract The substrate specificity of an endo-(1→4)-β- d -xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β- d -xylotriosides. In addition to (1→4) linkages, the enzyme could cleave (1→3) and (1→2) linkages adjacent to a (1→4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1→3) linkage that attached a terminal xylopyranosyl group to a (1→4)-linked xylobiosyl moiety. The enzyme did not attack α- d -xylosidic linkages. The rate of cleavage of (1→4) linkages was much higher than those of other linkages at 0.5m m substrate, but the rates were comparable at 20m m substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
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Hydrolysis of (1→3)- and (1→2)-β-d-xylosidic linkages by an endo-(1→4)-β-d-xylanase of Cryptococcus albidus
Carbohydrate Research, 1990Co-Authors: Maria Vrsanska, Jan Hirsch, Pavol Kovac, Peter BielyAbstract:Abstract The substrate specificity of an endo-(1→4)-β- d -xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β- d -xylotriosides. In addition to (1→4) linkages, the enzyme could cleave (1→3) and (1→2) linkages adjacent to a (1→4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1→3) linkage that attached a terminal xylopyranosyl group to a (1→4)-linked xylobiosyl moiety. The enzyme did not attack α- d -xylosidic linkages. The rate of cleavage of (1→4) linkages was much higher than those of other linkages at 0.5m m substrate, but the rates were comparable at 20m m substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
Indu Shekhar Thakur - One of the best experts on this subject based on the ideXlab platform.
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ethanol from sugar cane bagasse of pulp and paper mill effluent by Cryptococcus albidus and saccharomyces cerevisiae
Energy Sources Part A-recovery Utilization and Environmental Effects, 2015Co-Authors: Indu Shekhar Thakur, Anjali SinghalAbstract:Cryptococcus albidus and Saccharomyces cerevisiae was used for separate hydrolysis and fermentation of sugar cane bagasse for production of ethanol. Lignocellulolytic enzymes, CMCase (34 U/ml), FPase (3 U/ml), β-glucosidase (2.3 U/ml), laccase (32 U/ml), and xylanase (12 U/ml), were assayed by fungus, however, after optimization of process parameters, an increase of 1.5-fold sugar (375 mg/g) from bagasse and production of lignocellulolyic enzymes were determined. The sugar produced by sugar cane bagasse was subsequently treated by Saccharomyces cerevisiae, indicating enhanced production of ethanol at 40 h was 38.4 g/L, reached to a maximum at 50 h, and then it was decreased.
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biopulping of bagasse by Cryptococcus albidus under partially sterilized conditions
International Biodeterioration & Biodegradation, 2015Co-Authors: Anjali Singhal, Prashant Kumar Jaiswal, Indu Shekhar ThakurAbstract:Abstract Cryptococcus albidus was used for biopulping bagasse under partially sterilized conditions to access its potential industrial application in the pulp and paper industry. Enzyme analysis of C. albidus treated bagasse samples was carried out at different time periods (days 15, 30, and 60). Another set of bagasse was maintained in similar culture conditions without C. albidus inoculum (control) to assess the effect of C. albidus treatment. The proportion of cellulose degrading enzymes was found to be much lower (3.0–3.5%) as compared to the control samples (21–56%). Scanning electron microscopy (SEM) clearly demonstrated surface colonization and pit formation. Fourier-transformation infrared spectroscopy (FT-IR) indicated the chemical modification of bagasse. The signature peak for cellulose was found to be prominent in C. albidus treated samples. Denaturing gradient gel electrophoresis (DGGE) confirmed the presence of C. albidus throughout the experiments. It was evident that C. albidus was able to suppress the growth of a native population. After 60 days both control and treated bagasse were given a kraft pulping treatment. The kappa number of C. albidus treated bagasse decreased by 42% while in control samples it was found to be decreased by 39% only. There was increase in viscosity/kappa number ratio after treatment.
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optimization of growth media for enhanced production of laccase by Cryptococcus albidus and its application for bioremediation of chemicals
Journal of Environmental Engineering and Science, 2013Co-Authors: Anjali Singhal, Gaurav Choudhary, Indu Shekhar ThakurAbstract:Cryptococcus albidus, isolated from the sediments of Century Pulp and Paper Mill, Lalkuan, Nainital, Uttarakhand, India, produced a copper containing oxidase, laccase, that was capable of degrading environmental pollutants. Bagasse was the most efficient inducer for laccase production. The Taguchi approach was used to optimize the growth media for five factors, i.e., pH, copper sulphate, carbon, nitrogen, and the inducer at four levels using an M-16 orthogonal array. The optimum conditions for laccase production were pH (6), CuSO4 (2 mmol/L), meat peptone (0·5%), glucose (0·1%), and bagasse (1·0%). After optimization, laccase production increased seven times from 32 to 219 IU/mg. The inducer (bagasse) had maximum effect on laccase production leading to 52% increase, while pH had minimum effect with 7% increase. Growth media with laccase activity (2 U/mL) was applied for the bioremediation of dyes, effluent, and chemical compounds. These experiments showed that the growth media with laccase activity (2 U...
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assessment of Cryptococcus albidus for biopulping of eucalyptus
Preparative Biochemistry & Biotechnology, 2013Co-Authors: Anjali Singhal, Prashant Kumar Jaiswal, Alka Thapliyal, Indu Shekhar ThakurAbstract:Cryptococcus albidus shows delignification activity in nature. It was used for the biopulping of eucalyptus wood (Eucalyptus grandis) to access its potential for industrial application in the pulp and paper industry. Enzyme analysis on days 15, 30, and 60 showed the presence of laccase and xylanase as key enzymes. The production of endo-glucanase (CMCase) and exo-glucanase (FPase) was very low. Scanning electron microscopy (SEM) showed the surface colonization of wood and loosening of wood fibers in C. albidus-treated samples. Fourier-transformation infrared spectroscopy (FT-IR) indicated the chemical modification of eucalyptus wood. Denaturing gradient gel electrophoresis (DGGE) analysis on days 15, 30, and 60 confirmed the presence of C. albidus throughout the experiments. Cryptococcu albidus was able to suppress the growth of a native population. Further, after 60 days both the control and treated eucalyptus wood chips were given kraft pulping treatment. The kappa number of pulp of control wood was 21 ...
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two step sequential treatment of pulp and paper mill effluent by Cryptococcus albidus and emericella nidulans var nidulans in 2l bioreactor
Canadian Journal of Chemical Engineering, 2012Co-Authors: Anjali Singhal, Indu Shekhar ThakurAbstract:A number of studies had shown biological treatment of pulp and paper mill effluent. However, almost all the studies have focused on reduction in physical and chemical parameters. Toxicity analysis, though very important, has been neglected. Thus in this study genotoxicity along with colour and lignin content were studied. Treatment of effluent, generated at the pulping stage in pulp and a paper mill, was done using two fungal strains, Cryptococcus albidus and Emericella nidulans var. nidulans, in sequential manner in 2 L bioreactor. Two different treatments were given. In treatment (I) effluent was first treated by C. albidus (stage A) and this treated effluent was further treated by E. nidulans var. nidulans (stage B). In treatment (II) effluent was first treated by E. nidulans var. nidulans (stage C) and this treated effluent was further treated by C. albidus (stage D). Treatment (I) was more efficient than treatment (II) with 71%, 51%, 44% and 70% reduction in colour, lignin, COD and genotoxicity, respectively. Class distribution of comets also showed that treatment (I) was more efficient than treatment (II). Colour content showed very good correlation (r2 = 0.99) with effluent toxicity. The effluent treatment process (I) can be scaled up for industrial use. © 2011 Canadian Society for Chemical Engineering
Ho Nam Chang - One of the best experts on this subject based on the ideXlab platform.
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enhanced microbial lipid production by Cryptococcus albidus in the high cell density continuous cultivation with membrane cell recycling and two stage nutrient limitation
Journal of Industrial Microbiology & Biotechnology, 2018Co-Authors: Rongzhan Fu, Longan Shang, Christopher J Brigham, Ho Nam ChangAbstract:As a potential feedstock for biofuel production, a high-cell-density continuous culture for the lipid production by Cryptococcus albidus was investigated in this study. The influences of dilution rates in the single-stage continuous cultures were explored first. To reach a high-cell-density culture, a single-stage continuous culture coupled with a membrane cell recycling system was carried out at a constant dilution rate of 0.36/h with varied bleeding ratios. The maximum lipid productivity of 0.69 g/L/h was achieved with the highest bleeding ratio of 0.4. To reach a better lipid yield and content, a two-stage continuous cultivation was performed by adjusting the C/N ratio in two different stages. Finally, a lipid yield of 0.32 g/g and lipid content of 56.4% were obtained. This two-stage continuous cultivation, which provided a higher lipid production performance, shows a great potential for an industrial-scale biotechnological production of microbial lipids and biofuel production.
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exploring low cost carbon sources for microbial lipids production by fed batch cultivation of Cryptococcus albidus
Biotechnology and Bioprocess Engineering, 2011Co-Authors: Ho Nam Chang, Longan Shang, Jindalrae ChoiAbstract:Volatile fatty acids (VFAs), acetic acid, acetates, and ethanol were used as carbon sources for the production of microbial lipids using Cryptococcus albidus in batch cultures. C. albidus utilized organic acids less than glucose in the production of lipids, resulting in a lipid yield coefficient on VFAs of 0.125 g/g. In a two-stage batch culture, the lipid content increased to 43.8% (w/w) when VFAs were used as the sole carbon source in the second stage, which was two times higher than that of the batch culture. Furthermore, a 192 h, two-stage fed-batch cultivation of C. albidus produced a dry cell weight, lipid concentration, and lipid content of 26.4 g/L, 14.5 g/L, and 55.1% (w/w), respectively. The fed-batch culture model used in this study featured pure VFA solutions, with intermittent feeding, under oxygen-enriched air supply conditions. This study investigated several alternative carbon sources to reduce the cost of microbial lipids production and proved the feasibility of using VFAs as the carbon source for the provision of a high lipid content and productivity.
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the effect of volatile fatty acids as a sole carbon source on lipid accumulation by Cryptococcus albidus for biodiesel production
Bioresource Technology, 2011Co-Authors: Ho Nam Chang, Longan Shang, Jindalrae Choi, Jongwon KangAbstract:The use of volatile fatty acids (VFAs) for microbial lipid accumulation was investigated in flask cultures of Cryptococcus albidus. The optimum culture temperature and pH were 25 degrees C and pH 6.0, respectively, and the highest lipid content (27.8%) was obtained with ammonia chloride as a nitrogen source. The lipid yield coefficient on VFAs was 0.167 g/g of C. albidus with a VFAs (acetic, propionic, butyric acids) ratio of 8:1:1, which was in good agreement with a theoretically predicted lipid yield coefficient of the VFAs as a carbon source. The major fatty acids of the lipids accumulated by C. albidus were similar to those of soybean oil and jatropha oil. A preliminary cost analysis shows that VFAs-based biodiesel production is competitive with current palm and soybean based biodiesels. Further process development for lower aeration cost and higher lipid yield will make this process more economical. (C) 2010 Elsevier Ltd. All rights reserved.
Pavol Kovac - One of the best experts on this subject based on the ideXlab platform.
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hydrolysis of 1 3 and 1 2 β d xylosidic linkages by an endo 1 4 β d xylanase of Cryptococcus albidus
Carbohydrate Research, 1990Co-Authors: Maria Vrsanska, Jan Hirsch, Pavol Kovac, Peter BielyAbstract:Abstract The substrate specificity of an endo-(1→4)-β- d -xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β- d -xylotriosides. In addition to (1→4) linkages, the enzyme could cleave (1→3) and (1→2) linkages adjacent to a (1→4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1→3) linkage that attached a terminal xylopyranosyl group to a (1→4)-linked xylobiosyl moiety. The enzyme did not attack α- d -xylosidic linkages. The rate of cleavage of (1→4) linkages was much higher than those of other linkages at 0.5m m substrate, but the rates were comparable at 20m m substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
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Hydrolysis of (1→3)- and (1→2)-β-d-xylosidic linkages by an endo-(1→4)-β-d-xylanase of Cryptococcus albidus
Carbohydrate Research, 1990Co-Authors: Maria Vrsanska, Jan Hirsch, Pavol Kovac, Peter BielyAbstract:Abstract The substrate specificity of an endo-(1→4)-β- d -xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β- d -xylotriosides. In addition to (1→4) linkages, the enzyme could cleave (1→3) and (1→2) linkages adjacent to a (1→4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1→3) linkage that attached a terminal xylopyranosyl group to a (1→4)-linked xylobiosyl moiety. The enzyme did not attack α- d -xylosidic linkages. The rate of cleavage of (1→4) linkages was much higher than those of other linkages at 0.5m m substrate, but the rates were comparable at 20m m substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.