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: Rice microarray analysis showed that a number of stress-related genes are induced by external addition of L-ascorbic acid (AsA), and XIP-type xylanase inhibitors were suggested to be specialized in their function and involved in defense mechanisms in rice.
Abstract: Rice microarray analysis showed that a number of stress-related genes are induced by external addition of L-ascorbic acid (AsA). The gene designated as AK073843 which is homologous to class X chitinase was found to exhibit the highest induction among these genes. However, its crucial residues within the chitinase active site are substituted with other residues, suggesting that the protein has no chitinase activity. The recombinant protein which is encoded by the AK073843 gene produced in Escherichia coli has xylanase inhibitor activity, indicating that the gene encodes a novel rice XIP-type xylanase inhibitor protein (OsXIP). The expression of OsXIP was enhanced not only by exogenous AsA treatment but also by various stresses such as citrate and sodium chloride treatments, and wounding; however, it was not influenced by increasing endogenous AsA content. External AsA treatment caused a significant increase in electrolyte leakage from rice root. These results suggested that OsXIP was induced by stress which is caused by external AsA treatment. Rice XIP-family genes, OsXIP, riceXIP and RIXI, showed differential organ-specific expression. Also, these genes were differentially induced by stress and stress-related phytohormones. The transcripts of OsXIP and riceXIP were undetectable under normal conditions, and were drastically induced by wounding and methyl jasmonate (MeJA) treatment in the root. RIXI was constitutively expressed in the shoot but not induced by wounding and stress-related phytohormones. Thus, XIP-type xylanase inhibitors were suggested to be specialized in their function and involved in defense mechanisms in rice.
52 citations
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TL;DR: A newly isolated Bacterium strain named UEB-FK was selected from Tunisian Sahara, exhibiting the highest clear zone on agar plates containing oat spelt xylan by staining with Congo red, and prebiotic effect of XOS was evaluated by in vitro fermentation using known probiotic strains.
52 citations
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TL;DR: It appeared that the unique polymeric structure of raw OPFL favored cellulases and xylanase productions, and the enzyme complex that comprised of four endo-β-1,4-xylanases and endoglucanases showed thermophilic and acidophilic characteristics at 50-60 °C and pH 3.0.
52 citations
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TL;DR: The gene encoding a glycosyl hydrolase family 3 xylan 1,4-beta-xylosidase, xlnD, was successfully cloned from Aspergillus niger strain ATCC 10864 and was shown to efficiently hydrolyze small xylo-oligomers to monomericxylose, making it a critical hydrolytic activity in cases where xylose is to be recovered from biomass conversion processes.
Abstract: The gene encoding a glycosyl hydrolase family 3 xylan 1,4-beta-xylosidase, xlnD, was successfully cloned from Aspergillus niger strain ATCC 10864. The recombinant product was expressed in Aspergillus awamori, purified by column chromatography, and verified by matrix-assisted laser desorption ionization, tandem time of flight (MALDI-TOF/ TOF) mass spectroscopy of tryptic digests. The T max was determined using differential scanning microcalorimetry (DSC) to be 78.2 °C; the K m and k cat were found to be 255 μM and 13.7 s−1, respectively, using pNP-β-d-xylopyranoside as substrate. End-product inhibition by d-xylose was also verified and shown to be competitive; the K i for this inhibition was estimated to be 3.3 mM. XlnD was shown to efficiently hydrolyze small xylo-oligomers to monomeric xylose, making it a critical hydrolytic activity in cases where xylose is to be recovered from biomass conversion processes. In addition, the presence of the XlnD was shown to synergistically enhance the ability of an endoxylanase, XynA from Thermomyces lanuginosus, to convert xylan present in selected pretreated lignocellulosic substrates. Furthermore, the addition of the XynA/XlnD complex was effective in enhancing the ability of a simplified cellulase complex to convert glucan present in the substrates.
52 citations
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TL;DR: Partially purified xylanase was used in whole-wheat bread manufacturing to study its effect on the quality attributes of the bread during storage at room temperature (25°± 2°2C) and refrigerated temperature (4°± 1°1C) as discussed by the authors.
Abstract: Partially purified xylanase was used in whole-wheat bread manufacturing to study its effect on the quality attributes of the bread during storage at room temperature (25 ± 2C) and refrigerated temperature (4 ± 1C). Incorporation of xylanase resulted in reduced water absorption for dough preparation and reduced moisture loss from bread during storage. Addition of xylanase resulted in increased specific volume, increased shelf life, lower firmness during storage, reduced staling and brighter color of bread compared with that prepared without enzyme. Total color difference ΔE increased with storage time, but the extent of increase was lower in xylanase-supplemented bread. Glass transition temperature increased slowly during storage with significant (P < 0.05) enthalpy change. Rate of increase of firmness during storage was lower in xylanase-supplemented bread as compared with control. Xylanase supplementation resulted in improved sensory attributes of bread.
Practical Applications
Inadequate rising of dough leading to hardness, reduced volume and grainy mouthfeel results due to presence of bran in whole-wheat bread. Additives are therefore used to overcome this problem. Use of hydrolase in whole-wheat bread results in better color and flavor, softer texture, longer shelf life, fiber-rich nutritious bread. Partially purified microbial xylanase was used in the present study to produce whole-wheat bread with better sensory properties.
52 citations