Showing papers on "Xylanase published in 1983"
TL;DR: Two isolates of Sclerotinia sclerotiorum, B24 and SS41, were both able to produce polygalacturonase, cellulase and xylanase in infected sunflower stems, but these enzymes were severely inhibited at pH 6·0, which was the pH of the SS41-inoculated tissues.
Abstract: Two isolates of Sclerotinia sclerotiorum, B24 (strongly virulent) and SS41 (weakly virulent), were both able to produce polygalacturonase, cellulase and xylanase in infected sunflower stems These enzymes, even though active at their optimum pH's, were severely inhibited at pH 6·0, which was the pH of the SS41-inoculated tissues B24-inoculated tissues, when compared with SS41-inoculated ones, were characterized by a greater amount of oxalic acid, a lack of polyphenoloxidase (PPO) activity and a lower pH (pH 4·0) Oxalic acid proved to be an inhibitor of PPO activity and its effect was particularly strong at pH 4·0 The possible significance of these factors in the virulence of the S sclerotiorum isolates is discussed
208 citations
TL;DR: The ‐;xylosidase was demonstrated to play an important role in the overall conversion of heteroxylan into xylose that is analogous to the role of β‐glucosid enzyme in the saccharification of cellulose by cellulases.
Abstract: The growth of Trichoderma reesei QM9414 in shake flasks at 28 degrees C on hemicellulose substrates and bagasse resulted in rather low yields of hemicellulolytic enzymes (1.0-1.5 units/mL xylanase and 0.05-0.08 units/mL beta-xylosidase). The influence of pH on the synthesis of beta-xylosidase was greater than on the synthesis of xylanase. Both xylanase and beta-xylosidase showed optimal activity at pH 4-5 and 55-60 degrees C. Xylanase was stable at pH 2-10 but was heat labile and totally inactivated after 1 h at 65 degrees C. Enzyme stability towards heat could be increased in the presence of bovine serum albumin. The beta-xylosidase was more tolerant to heat, but stable over a pH range 2.5-6.0. The D-xylose inhibited both enzymes in a competitive manner. Hemicellulose (heteroxylan) was degraded to the extent of 30-40%within 24 h. The degree of hydrolysis decreased as the substrate concentration increased and increased with increased amounts of enzyme. Multiple enzyme doses resulted in increased saccharification in reduced times. The degree of hydrolysis was influenced by the amount of beta-xylosidase present in the hemicellulolytic enzyme preparation. The -;xylosidase was demonstrated to play an important role in the overall conversion of heteroxylan into xylose that is analogous to the role of beta-glucosidase in the saccharification of cellulose by cellulases.
158 citations
TL;DR: Quantification of hydrolysis products indicated that the enzyme′s greatest affinity was for the 2nd to 6th β-xylosidic linkages f...
Abstract: Extracellular endoxylanase (l,4-β-d-xylan xylanohydrolase [EC 3.2.1.8]) produced by Bacillus pumilus IPO, an isolate from soil in Thailand, was purified to homogeneity. The optimum pH and temperature of the purified xylanase for hydrolysis of larchwood xylan were 6.5 and 40°C. Its molecular weight was estimated to be 24,000 dalton by SDS-polyacrylamide gel electrophoresis and 20,000 dalton by equilibrium centrifugation. The number of amino acid residues per molecule was calculated to be 185, including one cysteine.The maximum degree of hydrolysis of larchwood xylan by the purified xylanase was 25%; xylobiose, xylotriose, xylotetraose and xylopentaose but not xylose were detected as end-products. trans-Xylosidase activity was indicated by the formation of xylobiose and xylotetraose from xylotriose and of xylopentaose and hexaose in addition to biose and triose from xylotetraose. Quantification of hydrolysis products indicated that the enzyme′s greatest affinity was for the 2nd to 6th β-xylosidic linkages f...
95 citations
TL;DR: A gene coding for xylanase synthesis in Bacillus subtilis was isolated by direct shotgun cloning using Escherichia coli as a host and shown to be present in a 3.9-kb insert within the PstI site of the plasmid pBR325.
88 citations
TL;DR: Partial characterization of an extracellular xylanase isolated by chromatography from Bacillus subtilis gave a molecular weight of 32,000 and optimum pH and temperature of 5.0 and 50 degrees C.
Abstract: Partial characterization of an extracellular xylanase isolated by chromatography from Bacillus subtilis gave a molecular weight of 32,000 and optimum pH and temperature of 50 and 50°C, respectively Km and Vmax values, determined with a soluble larchwood xylan, were 016% and 70 × 103 μmol min−1 mg−1 of enzyme respectively The amino acid composition showed more basic amino acid residues than in a previously characterized xylanase from a white-rot fungus
82 citations
75 citations
TL;DR: Analysis of enzymes expressed in the transformant cells indicated that neither enzyme was secreted into the culture medium, periplasm nor membrane bound, although xylanase but not β-xylosidase, was secreting into the medium in a B. pumilus culture.
Abstract: The 7.7 Mdal PstI fragment of Bacillus pumilus IPO containing genes for xylan degradation, xylanase, and β-xylosidase was inserted at the PstI site of pBR322 and cloned in E. coli C600. The hybrid plasmid thus formed was named pOXN29. The amount of xylanase and β-xylosidase expressed in E. coli harboring pOXN29 was about 6% and 20% of the activity produced by the donor, B. pumilus. The reverse orientation of the inserted fragment resulted respectively in 5 times and 50 times increases in xylanase and β-xylosidase productivities. Both enzymes expressed in E. coli transformants were shown to be indistinguishable from those of B. pumilus by immunological and chemical criteria. Digestion of pOXN29 with BglII produced two fragments; one was 6.7 Mdal in size and contained the whole pBR322 and the β-xylosidase gene, and the other was 3.7 Mdal and coded for xylanase. Analysis of enzymes expressed in the transformant cells indicated that neither enzyme was secreted into the culture medium, periplasm nor membrane bound, although xylanase but not β-xylosidase, was secreted into the medium in a B. pumilus culture.
74 citations
Journal Article•
60 citations
TL;DR: The high recovery of cellulolytic enzymes indicates that the adsorption of these enzymes on cellulose is not irreversible, and the recovery of enzyme from the insoluble residues is high.
Abstract: Penicillium funiculosum produces a complete cellulase which brings about 97% hydrolysis of cotton and has high beta-glucosidase, xylanase, laminarinase, and lichenase activities. This article deals with the effect of different pretreatments on the hydrolysis of sugarcane bagasse by P. funiculosum enzymes and the recovery of enzyme from the insoluble residues. Enzymic saccharification of bagasse pretreated with hot 1N NaOH followed by neutralization with HCI and steam treated under pressure (7 kg/cm(2)) gave 63 and 59% saccharification, respectively, in 48 h. Hemicellulose is not lost in these pretreatments. With a 30% slurry of steam-treated bagasse, a semisolid mass containing 14% sugar was obtained. A 90% recovery of CMCase, beta-glucosidase, and filter paper activity from the hydrolysates was obtained under the following conditions: (1) maintaining the ratio of enzyme to substrate high by stepwise addition of substrate, (2) brief grinding of the residual substrate with glass powder, and (3) addition of 0.4% Tween-80 to the eluting buffer. The high recovery of cellulolytic enzymes indicates that the adsorption of these enzymes on cellulose is not irreversible.
48 citations
TL;DR: In this paper, the authors studied the mechanism of attachment of arabinose residues to xylose residues in the arabinoxylan and the mode of action of the xylanase on the arbinoxylan.
Abstract: The hydrolysis of corncob arabinoxylan by a Streptomyces xylanase produced several kinds of oligosaccharides containing both arabinose and xylose residues, three of which have been identified as O-β-d-xylopyranosyl-(1→4)-O-[α-l-arabinofuranosyl-(1?3)]-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (A1X3II), O-β-d-xylopyranosyl-(1→4)-O-α-d-xylopyranosyl-(1?2)-O-α-l-arabinofuranosyl-(1?3)]-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (A1X4I) and O-β-d-xylopyranosyl-(1?2)-O-α-l-arabinofuranosyl-(1?3)-O-β-d-xylopyranosyl-(1→4)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (A1X4-II). On the basis of the structures of the above oligosaccharides, the mode of attachment of arabinose residues to xylose residues in the arabinoxylan and the mode of action of the xylanase on the arabinoxylan are discussed.
43 citations
TL;DR: Aspergillus fumigatus (Fresenius), IMI 246651, A.T.C. 46324, produces two beta-glucosidase enzymes, cotton-solubilizing activity, xylanase and endoglucanase enzymes which can be separated by gel-filtration chromatography.
Abstract: Aspergillus fumigatus (Fresenius), IMI 246651, ATCC 46324, produces two beta-glucosidase enzymes, cotton-solubilizing activity, xylanase and endoglucanase enzymes which can be separated by gel-filtration chromatography The major endoglucanase does not bind to concanavalin A-Sepharose and does not stain with periodic acid/Schiff reagent It is homogeneous on polyacrylamide isoelectric focusing (pI = 71) and has a molwt of 12500 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis The endoglucanase produces glucose and a mixture of oligosaccharides from cellulose; the purified enzyme has a small dextranase activity It is stable at 50 degrees C and pH 6
TL;DR: These new cellulase deficient strains from Sporotrichum pulverulentum have been isolated by spontaneous and induced mutations, and produce considerably higher amounts of phenol oxidases (Pox) than either parent type.
Abstract: In order to better understand which enzyme are of importance in lignin degradation, new cellulase deficient strains from Sporotrichum pulverulentum have been isolated by spontaneous and induced mutations from both wild type and from the earlier studied cellulase deficient strain 44. These new strains are xylanase positive (Xyl+), and produce considerably higher amounts of phenol oxidases (Pox) than either parent type. The new strains have been compared with the wild type and strain 44 with respect to their ability to release 14CO2 from a) vanillic acid labelled in the carboxyl, methoxyl and ring carbons; b) the dimer (4-methoxy-14C)-veratryl-glycerol-β-guaiacyl ether; c) 14C-ring-labelled DHP and 14C[β-carbon side chain] labelled DHP.
01 Jan 1983
TL;DR: From these experiments it is concluded that the contiuous culture experiments with hemicellulosic material and/or starch have to be performed with recycling of the cells and the extracellular enzymes.
Abstract: Several thermophilic and extreme thermophilic anaerobic bacteria can utilize hemicellulose (xylan polymer) from birch- and beechwood directly. Thermoanaerobacter ethanolicus JW200 exhibited the highest ethanol formation, although the extracellular xylanase and xylosidase activities were very low. All bacteria rapidly utilized xylose before the polymers were utilized at a lower rate. With resting cell suspensions of T. ethanolicus and its mutants, the ethanol formation rates were as high as 60 mmol (2.76 g) and 30 mmol (1.3 g) ethanol per liter per hour from glucose and xylose, respectively. After 1 hour the ethanol productions in the concentrated cell suspensions were linear for over 10 hours from glucose or xylose; however, with soluble starch (DE 10) the rates were increasing with time. From these experiments it is concluded that the contiuous culture experiments with hemicellulosic material and/or starch have to be performed with recycling of the cells and the extracellular enzymes. 25 references, 6 figures, 3 tables.
TL;DR: For enhanced production of cellulase and xylanase by the mixed culture of T. reesei D1-6 and A. wentii Pt 2804, the composition of medium has been optimized.
Abstract: For enhanced production of cellulase and xylanase by the mixed culture ofT. reesei D1-6 andA. wentii Pt 2804, the composition of medium has been optimized.
TL;DR: Xylanases excreted by the fungus Sporotrichum dimorphosporum have been separated by chromatography on DEAE-Sephadex at pH 7 into Fractions I and II, suggestive of a new mechanism for regulation of hydrolysis.
TL;DR: Serine and threonine were found to be the most abundant amino acids and these enzymes are very acidic proteins.
Abstract: When wheat straw was used as carbon source, Sporotrichum thermophile produced large amounts of xylanase extracellularly in addition to CM-cellulase and Avicelase. These enzymes were isolated by alcohol precipitation, desalting and column chromatography. The molecular weights were estimated to be 25,000 65,000 and 84,000 for xylanase, CM-cellulase and Avicelase respectively. Serine and threonine were found to be the most abundant amino acids and these enzymes are very acidic proteins.
TL;DR: A beta-1,4-xylanase has been purified from the mixture of carbohydrate-degrading enzymes found in a commercial preparation from cultures of Trichoderma viride and degrades xylans from larch and pear cell walls in an apparently endo-fashion.
Abstract: A beta-1,4-xylanase has been purified from the mixture of carbohydrate-degrading enzymes found in a commercial preparation from cultures of Trichoderma viride. Purification from the desalted enzyme mixture is accomplished either by preparative isoelectric focusing or in two-column chromatographic steps. The xylanase has maximal activity at pH 5.0 and a molecular weight of approximately 13,000 daltons. The enzyme loses activity when heated to above 45 degrees C. The xylanase degrades xylans from larch and pear cell walls in an apparently endo-fashion.
TL;DR: The cellulase was used to hydrolyze cellulose (spruce sulfite pulp) and various lignocellulosic waste materials (newspaper, wheatstraw, cornstover, wood and reed grass a.o.).
Abstract: Cellulase was produced by cultivating T. reesei QM 9414 and MCG 77 on spruce sulfite pulp. The solid enzyme prepared by acetone precipitation had 0.73 FPU/mg, 0.2 units s-glucosidase/mg and 10 units xylanase/mg. The average molecular weight was 48000 dalton. Analytical and preparative (20 mg) separation of the cellulase by chromatofocusing revealed the presence of 18 different proteins. Identified were: two exocellulases (C1 -enzymes), five endocellulases (Cx -enzymes), one s-glucosidase, one galacto-mannase, two xylanases and one s-xylosidase. The cellulase was used to hydrolyze cellulose (spruce sulfite pulp) and various lignocellulosic waste materials (newspaper, wheatstraw, cornstover, wood and reed grass a.o.). With 10, 5, 2.5, 1 and 0.5% cellulose slurries percentage of saccharification (24 hours) was 25, 42, 45, 53 and 69 %. Saccharification increased with increasing enzyme concentration up to a level of 0.60 FPU/ml and 0.36 units s-glucosidase/ml. A further increase of either one of the e...
TL;DR: Cultures of Aspergillus fumigatus IMI 246651, ATCC 46324 produced larger amounts of extracellular xylanase and cellulase when grown on hay or straw than when growing on CF11 cellulose.
Abstract: Cultures of Aspergillus fumigatus IMI 246651, ATCC 46324 produced larger amounts of extracellular xylanase and cellulase when grown on hay or straw than when grown on CF11 cellulose. The organism produced xylanase enzymes when grown on partially purified xylans but the amount of cellulase produced was much reduced.
TL;DR: Pleurotus sajor-caju, an edible mushroom, elaborated both cellulase and xylanase activities on cellulose medium, and the optimal initial pH for cellulase production was 5.0 as mentioned in this paper.
Abstract: Pleurotus sajor-caju, an edible mushroom, elaborated both cellulase and xylanase activities on cellulose medium. The optimal initial pH for cellulase production was 5.0. The pH and temperature optima for cellulase activity were 5.0 and 45°C respectively. The maximum cellulolytic activity obtained in shake flask on cellulose medium was attained in 6 – 8 days. Cellulase activity (FPA) produced on the mushroom bed remained more or less constant during the first 20 days of fruit body formation at 0.24 IU/g cellulosic bed material.
TL;DR: It was found that the presence of pectinase does not appear to facilitate the hydrolysis of cellulose in plant material through any cell-separating mechanism, and it was concluded that cellulase and xylanase activities are the important activities in the practical hydrolyzing of cellulosic materials and that lignin is the real limiting factor.
Abstract: The present study was undertaken to determine whether T. reesei produces pectinolytic enzymes and, if so, to determine their action pattern and specificity. The aim was also to find out the practical importance of pectinolytic activity in the hydrolysis of cellulosic materials. It was found that the presence of pectinase does not appear to facilitate the hydrolysis of cellulose in plant material through any cell-separating mechanism. It is concluded that cellulase and xylanase activities are the important activities in the practical hydrolysis of cellulosic materials and that lignin is the real limiting factor. (Refs. 12).
TL;DR: Investigation ofSaccharification of ball-milled winter wheat by an enzyme preparation from Trichoderma reesei containing both cellulase and xylanase activities found differences in degradability of as much as 22% were recorded.
Abstract: Saccharification of ball-milled winter wheat by an enzyme preparation from Trichoderma reesei containing both cellulase and xylanase activities has been investigated. Straw from different cultivars of winter wheat differed in the amount of reducing sugars released by the enzymes and by the buffer alone. Although only seven cultivars were tested, differences in degradability of as much as 22% were recorded. Differences of this magnitude are likely to be of economic significance when considering the recycling of cereal straws. It is therefore important that account is taken of the cultivar of cereal straw to be used.
01 Jan 1983
TL;DR: The production and thermal stability characteristics of cellulase and xylanase enzymes from a thermophilic fungus, Thielavia terrestris have been investigated and some results on the enzymatic hydrolysis of wheat straw at high temperatures are shown.
Abstract: The production and thermal stability characteristics of cellulase and xylanase enzymes from a thermophilic fungus, Thielavia terrestris have been investigated. In addition, some results on the enzymatic hydrolysis of wheat straw at high temperatures are also shown. The ..beta..-glucosidase activity of 0.9 I.U./ml was found in the culture filtrate, and this enzyme preserved 80% of its original activity after 40 h. of exposure at 60/sup 0/C. Hydrolysis of a 6.8% wheat-straw suspension yielded 26.4% saccharification within 6-8 h at 64/sup 0/C. The advantages of using thermostable cellulases and xylanases for the hydrolysis of cellulosics are discussed. 40 references, 11 figures, 6 tables.
TL;DR: It is suggested that pectic polysaccharides with a high degree of esterification may play an important role in cell walls of Gramineae.
Abstract: Cellulase C1, cellulase Cx, and xylanase were isolated and purified from a cellulase preparation of Trichoderma viride as enzymes effective in the isolation of protoplasts from oat leaves. Pectin lyase which is specific for methyl-galacturonide linkages was also found to be a useful enzyme for the isolation of protoplasts from the tissues. This suggested that pectic polysaccharides with a high degree of esterification may play an important role in cell walls of Gramineae. It was necessary to use the mixture of cellulase C1, cellulase Cx, xylanase, and pectin lyase for the rapid isolation of protoplasts, while a small amount of protoplasts could be isolated from oat leaves by cellulase C1 plus xylanase or cellulase C1 plus pectin lyase. The mixture of four enzymes also was effective in the isolation of protoplasts from the leaves of wheat, barley, and corn.
06 Jan 1983
TL;DR: In this paper, six thermophilic fungi isolated from paddy straw compost were screened for xylanolytic activity and two of them were found to be in lignocellulose complex.
Abstract: Six thermophilic fungi isolated from paddy straw compost were screened for xylanolytic activity. Sporotrichum thermophile, and Acremonium alabamensis exhibited more xylanolytic activity in comparison with others. The xylanase production by these two fungi were more in lignocellulose complex of paddy straw. The enzyme was produced only in xylose or xylose-containing hermicelluloses indicating its inducible nature.
TL;DR: Physiological and biochemical characteristics of the organism were identical with those of Bacillus acidocaldarius, and % GC of DNA was close to that of the latter (61 ~ 62%).
Abstract: Taxonomic characteristics of a strain of thermophilic acidophilic bacillus, Bacillus sp. 11-1S, which had the ability to produce thermophilic acidophilic amylase and thermostable xylanase were examined. Cells of the organism were aerobic, heterotrophic, Gram-positive, spore-forming rods. It grew at temperatures between 45 and 70°C (optimum 65°C) in media of pHs ranging from 2.0 to 5.0 (optimum 3.5 ~ 4.0). Physiological and biochemical characteristics were identical with those of Bacillus acidocaldarius, and % GC of DNA (59%) was close to that of the latter (61 ~ 62%). From these results it was concluded that the organism belongs to B. acidocaldarius Darland and Brock.
TL;DR: In liquid cultures Aspergillus fumigatus degraded sugar-cane bagasse better than wheat and paddy straw and produced cellulase, xylanase, pectinase and protease when provided with sugar- canebagasse, wheat and Paddy straw as carbon sources.
Abstract: Aspergillus fumigatus degraded sugar-cane bagasse better than wheat and paddy straw. In liquid cultures it produced cellulase, xylanase, pectinase and protease when provided with sugar-cane bagasse, wheat and paddy straw as carbon sources. Enzyme production was higher on bagasse than on wheat and paddy straw. Maximum growth occurred on glucose and xylan and minimum on carboxymethyl cellulose when used as sole carbon sources. Production of cellulase and xylanase was maximum on xylan, pectinase on pectin and protease on glucose. Neither cellulase nor pectinase activity was detected in glucose medium.
01 Jan 1983
TL;DR: Pretreatment of orange peels with fungal enzyme preparations rich in xylanase, pectinase and cellulases was found to enhance extractability of oil by steam distillation, leading to significant increase in the amount of protein extracted.
Abstract: Pretreatment of orange peels with fungal enzyme preparations rich in xylanase, pectinase and cellulases was found to enhance extractability of oil by steam distillation Gas chromatographic studies revealed a several fold increase in limonene in the extract Similar pretreatment of defatted seed meals, lead to significant increase in the amount of protein extracted