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Xylanase
About: Xylanase is a research topic. Over the lifetime, 7099 publications have been published within this topic receiving 163793 citations.
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TL;DR: The gene, XYL1, encoding the major extracellular endo-beta 1,4-xylanase from the maize pathogen Cochliobolus carbonum was cloned using a synthetic, degenerate oligonucleotide based on a tryptic fragment from the purified enzyme to create a specific xylanase mutant by transformation-mediated gene disruption via homologous recombination.
Abstract: The gene, XYL1, encoding the major extracellular endo-beta 1,4-xylanase from the maize pathogen Cochliobolus carbonum was cloned using a synthetic, degenerate oligonucleotide based on a tryptic fragment from the purified enzyme. The deduced product of XYL1 has a M(r) of 20,869 and a predicted pI of 9.1, in good agreement with the measured M(r) and pI of the purified enzyme. The XYL1 product has strong amino acid identity to seven endo-beta 1,4-xylanases from six prokaryotes but no obvious similarity to 10 other prokaryotic endoxylanases or a yeast endoxylanase. An internal fragment of the gene was used to create a specific xylanase mutant by transformation-mediated gene disruption via homologous recombination. Total extracellular xylanase activity in the mutant was reduced by 85-94%. When analyzed by cation exchange HPLC, culture filtrates of the mutant and wild type had identical protein profiles, but the mutant lacked the major peak of UV absorption corresponding to the major xylanase activity. Xylanase II activity was also missing in the mutant, but xylanase III activity was still present. The XYL1 mutant grew as well as the wild type on sucrose, on corn cell walls, and on xylan. The pathogenicity of the mutant was indistinguishable from the wild type, indicating that XYL1 is not required for pathogenicity.
103 citations
TL;DR: Xylanase activity from naturally occurring color variants of Aureobasidium pullulans was associated with extracellular monomeric proteins of 20 to 21 kilodaltons, and specific activity of partially purified xylanase exceeded 2,000 IU/mg.
Abstract: Xylanase activity from naturally occurring color variants of Aureobasidium pullulans was associated with extracellular monomeric proteins of 20 to 21 kilodaltons. Xylanase represented nearly half the total extracellular protein, with a yield of up to 0.3 g of xylanase per liter. The specific activity of partially purified xylanase exceeded 2,000 IU/mg. Xylanase from typically pigmented strains appeared similar to that from color variants with respect to molecular weight, pH and temperature optima, and specific activity of purified (but not crude) enzyme. However, xylanase from typical strains made up only about 1.0% of total extracellular protein. Xylanase from strains of Cryptococcus albidus was associated with abundant proteins of about 43 kilodaltons and showed much lower specific activity.
103 citations
TL;DR: Very low levels of cellulolytic enzyme activities were observed compared to lignin degrading enzymes by both the organisms.
103 citations
TL;DR: The xylanase activity, obtained with the optimized nutrient medium is 33% higher than the activity, achieved with the basic medium, and the predicted by the regression model optimum components of nutrient medium are as follows.
103 citations
TL;DR: The immobilized xylan enzyme is suitable to produce xylo-oligosaccahrides from corncob powder pre-treated with dilute alkaline solution and showed a higher thermal stability than the free xylanase.
102 citations