Search results for "Xylan"

Carboxymethylation of alkali extracted xylan for preparation of bio-based packaging films

2012

This study describes the synthesis of carboxymethylxylan (CMX) and investigates its suitability as a film for packaging applications. High-purity polymeric xylan was extracted from commercial bleached birch kraft pulp and converted to CMX with three different degrees of substitution (DSs). The water vapor sorption, mechanical, and barrier properties of the films prepared from CMX were tested. Increasing DS of CMX films resulted in an increase in elongation at break and a decrease in tensile strength and Young's modulus. The DS also affected the barrier properties of the films. CMX films with higher DS showed improved (reduced) oxygen permeability (OP), and the water vapor permeability (WVP)…

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…

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…

CCDC 942767: Experimental Crystal Structure Determination

2014

Related Article: Chi G. Fru, Louis P. Sandjo, Victor Kuete, Johannes C. Liermann, Dieter Schollmeyer, Samuel O. Yeboah, Renameditswe Mapitse, Berhanu M. Abegaz, Bonaventure T. Ngadjui, Till Opatz|2013|Phytochem.Lett.|6|676|doi:10.1016/j.phytol.2013.08.017

Effet de la rotation des cultures sur la microflore du sol et son activité

2009

Biopolymer interactions affect the functional properties of edible films based on agar, cassava starch and arabinoxylan blends

2009

Abstract Edible films based on the binary combination of agar (AG), cassava starch (CAS) and arabinoxylan (AX) were studied with regard to their microstructure, moisture barrier and mechanical properties. Though the films appear macroscopically homogeneous, electron microscopy observations reveal a phase separation and dispersion, respectively, in AG–CAS and AG–AX blend film structures, whereas the structure of CAS–AX blend films seems homogeneous. In case high moisture (84% and 99% RH), neither the combination of AG and CAS nor the addition of AX into CAS can improve film moisture barrier properties, except at a lower RH (57%). Conversely, water vapor permeability (WVP) of AG based film is…

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 …

Influence of Nitrogen Content on Grape Non-Saccharomyces Glycosidic Activities

2019

This study investigated the influence of nitrogen content on both β-glucosidase and β-xylosidase activities from non-Saccharomyces yeasts. Enzymatic activities were induced by the presence of xylan polysaccharides in the medium. Results show that optimizing β-glucosidase and β-xylosidase enzymatic activities can be determined not only by sugar or ethanol content or pH, but also by the concentration of N in the medium. This is the first work studying the influence of N content on glycolytic enzymes produced by non-Saccharomyces yeasts.

Conduction properties of thin films from a water soluble carbon nanotube/hemicellulose complex.

2018

We have examined the conductive properties of carbon nanotube based thin films, which were prepared via dispersion in water by non-covalent functionalization of the nanotubes with xylan, a type of hemicellulose. Measurements of low temperature conductivity, Kelvin probe force microscopy, and high frequency (THz) conductivity elucidated the intra-tube and inter-tube charge transport processes in this material. The measurements show excellent conductive properties of the as prepared thin films, with bulk conductivity up to 2000 S cm−1. The transport results demonstrate that the hemicellulose does not seriously interfere with the inter-tube conductance. peerReviewed

From the forest to the plate – Hemicelluloses, galactoglucomannan, glucuronoxylan, and phenolic-rich extracts from unconventional sources as function…

2021

This study aimed to characterise pressurised hot water (PHW) extracts from nonconventional sources of functional carbohydrates and phenolic compounds in terms of antioxidant capacity, antiviral activity, toxicity, and human erythrocytes’ protection antidiabetic potential. PHW extracts of Norway spruce bark (E1 + E2) and Birch sawdust (E3 + E4) contained mostly galactoglucomannan and glucuronoxylan. In contrast, samples E5 to E9 PHW extracted from Norway spruce, and Scots pine bark are rich sources of phenolic compounds. Overall, phenolic-rich extracts presented the highest inhibition of α-amylase and α-glucosidase and protection against stable non-enveloped enteroviruses. Additionally, all …