Search results for "Xylanase"
showing 10 items of 10 documents
A multidomain xylanase from a Bacillus sp. with a region homologous to thermostabilizing domains of thermophilic enzymes
1999
The gene xynC encoding xylanase C from Bacillus sp. BP-23 was cloned and expressed in Escherichia coli. The nucleotide sequence of a 3538 bp DNA fragment containing xynC gene was determined, revealing an open reading frame of 3258 bp that encodes a protein of 120,567 Da. A comparison of the deduced amino acid sequence of xylanase C with known beta-glycanase sequences showed that the encoded enzyme is a modular protein containing three different domains. The central region of the enzyme is the catalytic domain, which shows high homology to family 10 xylanases. A domain homologous to family IX cellulose-binding domains is located in the C-terminal region of xylanase C, whilst the N-terminal r…
Cell wall-degrading enzymes produced in vitro by isolates of Phaeosphaeria nodorum differing in aggressiveness
2000
The relationships between in vitro production of cell wall-degrading enzymes and aggressiveness of three Phaeosphaeria nodorum isolates were investigated. When grown in liquid medium containing 1% cell wall from wheat leaves as the carbon source, the isolates secreted xylanase, α-arabinosidase, β-xylosidase, polygalacturonase, β-galactosidase, cellulase, β-1,3-glucanase, β-glucosidase, acetyl esterase and butyrate esterase. Time-course experiments showed different levels of enzyme production and different kinetics between isolates. A highly aggressive isolate produced more xylanase, cellulase, polygalacturonase and butyrate esterase than did the two weakly aggressive isolates. Xylanase was …
Toxicological Assessment of Recombinant Xylanase X22 in Wine
1999
Toxicological evaluation of xylanase X(22) from Aspergillus nidulans expressed in a wine yeast strain was carried out. The safety of the X(22) intake was assessed by digestibility, bioinformatic, and mouse short-term repeated dosing studies, although X(22) shows resistance to proteolytic degradation in the gastrointestinal system, is a minority protein component (<0.5 10(-)(6) %) of the produced wine, and shows no significant amino acid sequence homology to any known food allergens. The 4-week oral toxicity study was performed in Swiss mice at a dose level of 0.01, 0.1, or 1 mg/kg/day (these dosages correlate to 8, 80, and 800 times, respectively, the enzyme amount contained in 250 mL of wi…
Evaluation of Two Method to Measure Xylanase Activity in Relation with Rheological Effects of Xylanases on White Flour
2011
Many methods are available to measure the xylanase activity of enzymatic preparation. Most of method uses different substrates from those that will be hydrolyzed in various applications in food industry. This fact will lead to a deformed image about how evaluated xylanases will really act in a specific application. The aim of this study is to evaluate the activity of seven xylanase preparation with two method, a colorimetric method with birch insoluble xylan as substrate and a viscometric method with wheat soluble arabinoxylan as substrate.
Non-Saccharomyces Yeasts: An Enzymatic Unexplored World to be Exploited
2019
Abstract Fermentation, to obtain alcoholic beverages, is a process which implies the interaction of various microorganisms. This metabolic process is due to the action of yeasts, which can be divided into two groups, the Saccharomyces yeasts, particularly S. cerevisiae, and the non-Saccharomyces yeasts. Although they are considered spoilage microorganisms of the fruits, non-Saccharomyces yeasts possess some interesting applied characteristics and can be used in food industry. Some of the compounds produced by these microorganisms may be beneficial and improve the characteristics of the fermented beverages. In this chapter, recent advances in glycosidase, xylanase, lipase, esterase, protease…
pH control of the production of recombinant glucose oxidase in Aspergillus nidulans.
2004
Aims: Recombinant Aspergillus nidulans sVAL040, capable of synthesizing and secreting glucose oxidase derived from Aspergillus niger was used to study the influence of pH and carbon source on enzyme production. Methods and Results: Glucose oxidase gene (goxC) was expressed under transcriptional regulation by using the promoter of A. nidulans xlnB gene (encoding an acidic xylanase). A maximum specific glucose oxidase activity of approx. 10 U mg−1 protein and a maximum volumetric productivity of 29·9 U l−1 h−1 were obtained at pH 5·5, after 80 h of growth by using xylose as inducer. Enzyme volumetric productivity increased when xylans were used instead of xylose; however, specific glucose o…
Glucose and Ethanol Tolerant Enzymes Produced by Pichia (Wickerhamomyces) Isolates from Enological Ecosystems
2012
A total of 17 Pichia ( Wickerhamomyces ) isolates obtained from enological ecosystems in the Utiel-Requena Spanish region were characterized by physiological (using API 20C AUX strips and ID Yeast Plus System miniaturized identification systems) and molecular (PCR-RFLP and sequencing) techniques as belonging to the species P. fermentans, P. membranifaciens , and W. anomalus . Data support the reclassification of P. anomala as Wickerhamomyces anomalus . In order to characterize their enzymatic abilities, xylanase, β-glucosidase, lipase, esterase, protease, and pectinase qualitative and quantitative assays were made. Wickerhamomyces anomalus and P. membranifaciens were the most interesting sp…
Prebiotic effect of xylooligosaccharides produced from birchwood xylan by a novel fungal GH11 xylanase.
2017
34 p.-4 fig.-1 tab.
Bacteria from acidic to strongly alkaline insect midguts: Potential sources of extreme cellulolytic enzymes
2012
Abstract Bacterial isolates from the European Corn Borer (ECB) Ostrinia nubilalis and the coleopteran Colorado Potato Beetle (CPB) Leptinotarsa decemlineata midguts were identified and characterized. Twenty-four colonies, selected on solid media with cellulose as the sole carbon source and pH values ranging from 5 to 12, were identified through 16S sequencing as members of the genera Acinetobacter , Comamonas , Klebsiella , Microbacterium , Micrococcus and Sphingobacterium . A complete enzymatic characterization revealed widespread – albeit moderate – cellulase properties in all but one isolate and high xylanase activity in the four CPB isolates. Different enzymatic patterns in terms of opt…
Rheological Evaluation of Some Commercial Xylanases
2011
The arabinoxylans play and the xylanases play an important role breadmaking. For a better selection of xylanases, it is necessary to understand how they work in breadmaking. At the same activity, the xylanases have different effect on dough rheology. The xylanases activity measured through birch xylan hydrolysis it is not correlated with extensographic effects. Weak but better correlations were observed when the xylanase activity was measured as the ability to decrease the viscosity of soluble wheat arabinoxylans solution.