Topic
Xylanase
About: Xylanase is a research topic. Over the lifetime, 7099 publications have been published within this topic receiving 163793 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: Conditions of enzymatic hydrolysis leading to the best yields of xylose and xylooligosaccharides (DP 2-5) were investigated using substrate concentration in the range 0.5–3.5% (w/v), enzyme load 40–80 U/g of the substrate, and reaction time from 3 to 96 h, applying a 22 factorial design.
Abstract: Sugarcane bagasse hemicellulose was isolated in a one-step chemical extraction using hydrogen peroxide in alkaline media. The polysaccharide containing 80.9% xylose and small amounts of l-arabinose, 4-O-methyl-d-glucuronic acid and glucose, was hydrolyzed by crude enzymatic extracts from Thermoascus aurantiacus at 50 °C. Conditions of enzymatic hydrolysis leading to the best yields of xylose and xylooligosaccharides (DP 2-5) were investigated using substrate concentration in the range 0.5–3.5% (w/v), enzyme load 40–80 U/g of the substrate, and reaction time from 3 to 96 h, applying a 22 factorial design. The maximum conversion to xylooligosaccharides (37.1%) was obtained with 2.6% of substrate and xylanase load of 60 U/g. The predicted maximum yield of xylobiose by a polynomial model was 41.6%. Crude enzymatic extract of T. aurantiacus generate from sugarcane bagasse hemicellulose 39% of xylose, 59% of xylobiose, and 2% of other xylooligosaccharides.
128 citations
TL;DR: The xylanase of T. lanuginosus was found to be inducible by xylan containing C sources as well as by xylose, and the optimal pH values of all enzymes were determined.
128 citations
TL;DR: There is functional redundancy among the T2S secreted proteins of X. oryzae in promoting virulence on rice, and the pRR7 clone containing an intact xynB gene could complement the virulence-deficient phenotype of the lipA-xynB mutant.
Abstract: Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight, a serious disease of rice. We demonstrated earlier that the type II secretion system (T2S) is important for virulence of X. oryzae pv. oryzae and that several proteins, including a xylanase, are secreted through this system. In this study, the xynB gene encoding for the secreted xylanase was cloned as a 6.9-kb EcoRI fragment (pRR7) that also included a paralog called xynA. As in X. oryzae pv. oryzae, xynA and xynB are adjacent to each other in X. axonopodis pv. citri, whereas only the xynA homolog is present in X. campestris pv. campestris. Mutations in xynB but not xynA affect secreted xylanase activity. Western blot analysis using anti-XynB antibodies on exudates from infected rice leaves indicated that this xylanase is expressed during in planta growth. Another T2S-secreted protein was identified to be a lipase/esterase (LipA) based on the sequence tags obtained by tandem mass spectrometry analysis and biochemical assays. Mutations in either xynB or lipA partially affected virulence. However, a lipA-xynB double mutant was significantly reduced for virulence, and the pRR7 clone containing an intact xynB gene could complement the virulence-deficient phenotype of the lipA-xynB mutant. Our results suggest that there is functional redundancy among the T2S secreted proteins of X. oryzae pv. oryzae in promoting virulence on rice.
128 citations
TL;DR: The results indicated that the selected microorganisms, and the cultivation process, have great biotechnological potential.
128 citations
TL;DR: Chromogenic (fluorogenic) 4-methylumbelliferyl substrates were used to characterize the major activities of the multienzyme component, after the separation by isoelectric focusing (IEF) electrophoresis.
128 citations