Topic
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 potential application of plant produced recombinant xylanase for pulp and paper bleaching is demonstrated and was related to the amount xylan removed and microfibrils were visible on the fiber surface.
52 citations
TL;DR: Two endo-β-1,4-xylan xylanohydrolases (EC 3.2.8), XynA and XynB, from solid-state cultures of Penicillium capsulatum, were purified to apparent homogeneity as judged by electrophoresis and isoelectric focusing.
Abstract: Two endo-β-1,4-xylan xylanohydrolases (EC 3.2.1.8), XynA and XynB, from solid-state cultures ofPenicillium capsulatum, were purified to apparent homogeneity as judged by electrophoresis and isoelectric focusing. Each is a single subunit glycoprotein. XynA containing 97 mol carbohydrate·mol−1 protein, while XynB contains 63 mol·mol−1.M
r and pI values are 28 500, 5.0–5.2 (XynA) and 29 500, 5.0–5.2 (XynB), respectively. Both enzymes are most active at pH 4 and 47–48°C, and have half-lives of 32 min (XynA) and 13 min (XynB) at pH 4, 60°C. Each form catalyzed the hydrolysis of a variety of xylans, albeit with different degrees of efficiency. In addition, XynB catalyzed extensive degradation of barley β-glucan, CM-cellulose and, to a lesser extent, lichenan, but kinetic parameters indicate that it is primarily a xylanase. The products of hydrolysis of various xylans and xylopentaose differed for each enzyme and ranged from xylose to xyloheptaose depending on the substrate used. Each enzyme is endo-acting and has transferase as well as direct hydrolase activity. Inactivation byN-bromosuccinimide indicated the possible involvement of tryptophan in binding and/or catalysis.
52 citations
TL;DR: The gene encoding a novel modular xylanase from Cellulosimicrobium sp.
Abstract: The gene encoding a novel modular xylanase from Cellulosimicrobium sp strain HY-13 was identified and expressed in Escherichia coli, and its truncated gene product was characterized The enzyme consisted of three distinct functional domains, an N-terminal catalytic GH10 domain, a fibronectin type 3 domain, and C-terminal carbohydrate-binding module 2
52 citations
TL;DR: Data suggest that the primary function of the calcium binding domain is to increase the stability of the enzyme against thermal unfolding and proteolytic attack, and the possible mechanism by which the domain evolved is discussed.
52 citations
TL;DR: Bacillus circulans AB 16 showed high pH and thermal stability retaining 100% activity at 60 ∘C, pH 8 and 9 after 2.5 h of incubation.
Abstract: Bacillus circulans AB 16 was able to produce 50 IU/ml of xylanase, with negligible cellulase activity when grown on untreated wheat straw. The pH optimum of the crude enzyme was 6–7 with a temperature optimum of 80 ∘C. The enzyme showed high pH and thermal stability retaining 100% activity at 60 ∘C, pH 8 and 9 after 2.5 h of incubation. The residual activity at 70 ∘C after 2.5 h was 62% and 45% at pH 8 and 9, respectively. At 75 ∘C only 22.2% activity remained at pH 8 after 1 h incubation. Since Kraft pulp is alkaline this enzyme could be used for prebleaching of pulp at temperatures up to 70 ∘C without pH adjustment.
52 citations