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Journal ArticleDOI

Use of corncob for endoxylanase production by thermophilic fungus Thermomyces lanuginosus IOC-4145.

TL;DR: The production of cellulase-free end oxylanase by the thermophilic fungus Thermomyces lanuginosus was investigated insemisolid fermentation and liquid fermentation, and corncob, xylan, and xylose were the best inducers for endoxylanase production.
Abstract: The production of cellulase-f ree endoxylanase by the thermophilic fungus Thermomyces lanuginosus was investigated in semisolid fermentation and liquid fermentation. Different process variables were investigated in semisolid fermentation, employing corncob as the carbon source. The best results were with the following conditions: grain size = 4.5 mm, solid:liquid ratio = 1: 2, and inoculum size = 20% (v/v). Corncob, xylan, and xylose were the best inducers for endoxylanase production. Additionally, organic nitrogen sources were necessary for the production of high endoxylanase activities. The crude enzyme had optimum activity at pH 6.0 and 75°C, displaying a high thermostability. The apparent K m and V max were 1.77 mg of xylan/mL and 21.5 U/mg of protein, respectively.
Citations
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Journal ArticleDOI
TL;DR: There has been much industrial interest in xylan and its hydrolytic enzymatic complex, as a supplement in animal feed, for the manufacture of bread, food and drinks, textiles, bleaching of cellulose pulp, ethanol and xylitol production.
Abstract: Xylan is the principal type of hemicellulose. It is a linear polymer of beta-D-xylopyranosyl units linked by (1-4) glycosidic bonds. In nature, the polysaccharide backbone may be added to 4-O-methyl-alpha-D-glucuronopyranosyl units, acetyl groups, alpha-L-arabinofuranosyl, etc., in variable proportions. An enzymatic complex is responsible for the hydrolysis of xylan, but the main enzymes involved are endo-1,4-beta-xylanase and beta-xylosidase. These enzymes are produced by fungi, bacteria, yeast, marine algae, protozoans, snails, crustaceans, insect, seeds, etc., but the principal commercial source is filamentous fungi. Recently, there has been much industrial interest in xylan and its hydrolytic enzymatic complex, as a supplement in animal feed, for the manufacture of bread, food and drinks, textiles, bleaching of cellulose pulp, ethanol and xylitol production. This review describes some properties of xylan and its metabolism, as well as the biochemical properties of xylanases and their commercial applications.

1,214 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the production of CMCase and xylanase by a Brazilian strain of Thermoascus aurantiacus in solid state fermentation (SSF) using different agricultural residues (wheat bran, sugarcane bagasse, orange bagasse and corn straw) as substrates without enrichment of the medium and characterized the crude enzymes.

160 citations


Cites background from "Use of corncob for endoxylanase pro..."

  • ...and cost-effective medium ingredient, because it is largely produced as a by-product during the corn processing (3,15,22)....

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  • ...autantiacus, appeared to be superior to some others thermophilic fungi already described (3,5,16,21)....

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  • ...difference in level of enzyme production by different raw material is determined by many factors involved in the process, such as the presence of activator or inhibitor, surface area, diffusion of catabolite, pretreatment, content and sugar composition of this substrate (3,8)....

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Journal ArticleDOI
TL;DR: Experimental results show that alkali concentration, irradiation time (IT) and substrate concentration (SC) were main factors governing the saccharification of rice straw and hulls.

140 citations


Cites background from "Use of corncob for endoxylanase pro..."

  • ...It was well documented that the carbon source is an important variable for xylanases production, lignocellulosic materials appear to be a better substrates than xylan for producing xylanolytic enzymes (Damaso et al., 2000), conversely, Trichoderma reesei showed the highest levels of endoxylanase growing on cellulose (Olsson et al....

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Journal ArticleDOI
TL;DR: The high level of fully active recombinant xylanase obtained in P. pastoris makes this expression system attractive for fermentor growth and industrial applications.
Abstract: Highly efficient production of a Thermomyces lanuginosus IOC-4145 β-1,4-xylanase was achieved in Pichia pastoris under the control of the AOX1 promoter. P. pastoris colonies expressing recombinant xylanase were selected by enzymatic activity plate assay, and their ability to secrete high levels of the enzyme was evaluated in small-scale cultures. Furthermore, an optimization of enzyme production was carried out with a 23 factorial design. The influence of initial cell density, methanol, and yeast nitrogen base concentration was evaluated, and initial cell density was found to be the most important parameter. A time course profile of recombinant xylanase production in 1-liter flasks with the optimized conditions was performed and 148 mg of xylanase per liter was achieved. Native and recombinant xylanases were purified by gel filtration and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, circular dichroism spectroscopy, matrix-assisted laser desorption ionization-time of flight-mass spectrometry and physicochemical behavior. Three recombinant protein species of 21.9, 22.1, and 22.3 kDa were detected in the mass spectrum due to variability in the amino terminus. The optimum temperature, thermostability, and circular dichroic spectra of the recombinant and native xylanases were identical. For both enzymes, the optimum temperature was 75°C, and they retained 60% of their original activity after 80 min at 70°C or 40 min at 80°C. The high level of fully active recombinant xylanase obtained in P. pastoris makes this expression system attractive for fermentor growth and industrial applications.

126 citations


Cites background or methods from "Use of corncob for endoxylanase pro..."

  • ...lanuginosus xylanase, irrespective of the strain used, is semisolid medium, with corncob as the substrate (9)....

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  • ...de Janeiro, Brazil, under the code IOC-4145 (9)....

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  • ...Thermomyces lanuginosus was isolated from Brazilian soil and identified by Fundação Instituto Oswaldo Cruz, Rio de Janeiro, Brazil, under the code IOC-4145 (9)....

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  • ...The activities present in the culture media were also analyzed by the Somogyi-Nelson procedure, enabling us to quantify the amount of active protein made in the T. lanuginosus IOC-4145 and in the P. pastoris media....

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  • ...Several strains of the thermophilic fungus Thermomyces lanuginosus secrete high levels of xylanases, which are very active and stable at elevated temperatures (9, 27, 31)....

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References
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Journal Article
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.

289,852 citations

Journal ArticleDOI
TL;DR: In this paper, a collaborative investigation of assays for endo-1,4-β-xylanase activity based on production of reducing sugars from polymeric 4-O-methyl glucuronoxylan was conducted.

2,332 citations

Book
01 Jan 1999
TL;DR: The culture The process Strain Improvement Immobilization and Cell Culture Biochemical Engineering Special Topics as discussed by the authors The culture the process strain improvement Immobilisation and cell culture Biochemical engineering
Abstract: The Culture The Process Strain Improvement Immobilization and Cell Culture Biochemical Engineering Special Topics

882 citations

Journal ArticleDOI
TL;DR: The main goals in the enzyme-aided bleaching of kraft pulps have been the reduction of consumption of chlorine chemicals in the bleaching process and consequently lowering the AOX of the effluents.
Abstract: The utilization of hemicellulases in bleaching of kraft (sulphate) pulp is considered as one of the most important new large-scale industrial applications of enzymes. This is partly due to the great potential of an environmentally safe method. This method has in a short period also proven to be economically realistic. The main enzymes needed in the enzyme-aided bleaching have been shown to belong to the group of endo-/gb-xylanases. Xylanases act mainly on the relocated, reprecipitated xylan on the surface of the pulp fibres. Enzymatic hydrolysis of this specific type of xylan renders the structure of the fibres more permeable. The hydrolysis of xylan or mannan in the inner fibre layers may also enhance the bleachability. In practical process conditions, properties of the enzymes such as substrate specificity and the pH and temperature optima are of utmost importance. The benefits obtained by enzymes are dependent on the chemical bleaching sequence used as well as on the residual lignin content of pulp. The main goals in the enzyme-aided bleaching of kraft pulps have been the reduction of consumption of chlorine chemicals in the bleaching process and consequently lowering the AOX of the effluents. Enzymes have been applied as a pretreatment both in conventional (C/D)EDED and in ECF (elementary chlorine-free) bleaching sequences. In the production of TCF (totally chlorine-free) pulps, enzymes have also been successfully used for increasing the brightness of pulp.

669 citations