Xylanase activity of Clostridium cellulovorans, an anaerobic, mesophilic, cellulolytic bacterium, was characterized. Most of the activity was secreted into the growth medium when the bacterium was grown on xylan. Furthermore, when the extracellular material was separated into cellulosomal and noncellulosomal fractions, the activity was present in both fractions. Each of these fractions containe...

An esterase which is encoded within a Thermotoga maritima chromosomal gene cluster for xylan degradation and utilization was characterized after heterologous expression of the corresponding gene in Escherichia coli and purification of the enzyme. The enzyme, designated AxeA, shares amino acid sequence similarity and its broad substrate specificity with the acetyl xylan esterase from Bacillus pu...

Seeds from the myxospermous species Plantago ovata release a polysaccharide-rich mucilage upon contact with water. This seed coat derived mucilage is composed predominantly of heteroxylan (HX) and is utilized as a gluten-free dietary fiber supplement to promote human colorectal health. In this study, a gamma-irradiated P. ovata population was generated and screened using histological stains and...

A beta-1,4-xylan hydrolase (xylanase A) produced by Erwinia chrysanthemi D1 isolated from corn was analyzed with respect to its secondary structure and enzymatic function. The pH and temperature optima for the enzyme were found to be pH 6.0 and 35 degrees C, with a secondary structure under those conditions that consists of approximately 10 to 15% alpha-helices. The enzyme was still active at t...

A sulphated tin ion-exchanged montmorillonite (SO4/Sn-MMT) was successfully prepared by the ion exchange method of montmorillonite (MMT) with SnCl4, followed by the sulphation. This catalysis was applied as a solid acid catalyst for the heterogeneous catalytic transformations of xylose and xylan into furfural in the bio-based 2-methyltetrahydrofuran/H2O biphasic system. These prepared catalysts...

BACKGROUND Many agricultural and industrial food by-products are rich in cellulose and xylan. Their enzymatic degradation into monosaccharides is seen as a basis for the production of biofuels and bio-based chemicals. Lytic polysaccharide monooxygenases (LPMOs) constitute a group of recently discovered enzymes, classified as the auxiliary activity subgroups AA9, AA10, AA11 and AA13 in the CAZy ...

GAlactUronosylTransferase12 (GAUT12)/IRregular Xylem8 (IRX8) is a putative glycosyltransferase involved in Arabidopsis secondary cell wall biosynthesis. Previous work showed that Arabidopsis irregular xylem8 (irx8) mutants have collapsed xylem due to a reduction in xylan and a lesser reduction in a subfraction of homogalacturonan (HG). We now show that male sterility in the irx8 mutant is due t...

Microbial hydrolysis of lignocellulosic biomass is becoming increasingly important for the production of renewable biofuels to address global energy concerns. Hemicellulose is the second most abundant lignocellulosic biopolymer consisting of mostly xylan and other polysaccharides. A variety of enzymes is involved in complete hydrolysis of xylan into its constituent sugars for subsequent biofuel...

Compared with batch systems, flowthrough and countercurrent reactors have important potential advantages for pretreating cellulosic biomass, including higher hemicellulose sugar yields, enhanced cellulose digestibility, and reduced chemical additions. Unfortunately, they suffer from high water and energy use. To better understand these trade-offs, comparative data are reported on xylan and lign...

The effects of a double polyelectrolyte adsorption of poly(allylamine hydrochloride) (PAH) and xylan (Xyl) on a recycled unbleached softwood kraft pulp were studied. The kinetics of PAH adsorption on this pulp was analyzed by building adsorption isotherms and by estimating the surface nitrogen adsorbed through the X-ray photoelectron spectroscopy (XPS) technique. It was found that at pH 7.5, 0....