Wood is an important renewable material used by humans for a variety of downstream applications. The basic subcellular structure in wood is the cell wall, mainly consisting of the cross-linked polymers cellulose, hemicellulose, and lignin. Xylan is the main hemicellulose found in angiosperm wood, and its biosynthesis and effects on wood properties in hybrid aspen (Populus tremula x tremuloides)...

Caldicellulosiruptor lactoaceticus 6A, an anaerobic and extremely thermophilic bacterium, uses natural xylan as carbon source. The encoded genes of C. lactoaceticus 6A for glycoside hydrolase (GH) provide a platform for xylan degradation. The GH family 10 xylanase (Xyn10A) and GH67 α-glucuronidase (Agu67A) from C. lactoaceticus 6A were heterologously expressed, purified and characterized. Both ...

Background Consolidated bioprocessing (CBP) has attracted increasing attention since it can accomplish hydrolytic enzymes production, lignocellulose degradation and microbial fermentation in one single step. Currently, biobutanol is mainly produced by mesophilic and solventogenic clostridia, such as Clostridium beijerinckii and C. acetobutylicum, which cannot directly utilize lignocellulose, an...

Xylan is the major component of monocotyledon hemicelluloses of plant cell walls in which 13-1,4-linked D-xylose residues constitute the backbone of xylan. After cellulose, xylan is the most abundant renewable polysaccharide in nature, accounting for 20 to 30% of the dry weight of woody tissue. In order to maximize the hydrolysis of lignocellulosic residues by cellulase enzymes, synergistic act...

There is an increasing interest in utilizing xylan from hardwood in the food and non-food area. The liberation of xylan from the cell wall matrix of wood is, however, highly restricted by the strong interactions with the lignin network. Xylan stability against alkaline pulping is particularly high in Eucalyptus globulus owing to its peculiar structure containing galactosyl and glucosyl units at...

Xylan, a hemicellulosic component of the plant cell wall, is one of the most abundant polysaccharides in nature. In contrast to dicots, xylan in grasses is extensively modified by α-(1,2)- and α-(1,3)-linked arabinofuranose. Despite the importance of grass arabinoxylan in human and animal nutrition and for bioenergy, the enzymes adding the arabinosyl substitutions are unknown. Here we demonstra...

Yeasts able to grow on d-xylose were screened for the ability to hydrolyze xylan. Xylanase activity was found to be rare; a total of only 19 of more than 250 strains yielded a positive test result. The activity was localized largely in the genus Cryptococcus and in Pichia stipitis and its anamorph Candida shehatae. The ability to hydrolyze xylan was generally uncoupled from that to hydrolyze ce...

The reliability of xylan fermentation in distinguishing Bacteroides ovatus from Bacteroides thetaiotaomicron was examined with strains previously identified by DNA homology studies or bacteriophage sensitivity testing or both. All of the 12 B. ovatus strains produced acid ranging from pH 5.0 to 5.6 in peptone-yeast-xylan broth; none of the 19 B. thetaiotaomicron strains produced acid, and the f...

Since the addition of either ruminal fluid or a combination of phenylacetic and phenylpropionic acids (PAA/PPA) has previously been shown to dramatically improve cellulose degradation and growth of Ruminococcus albus, it was of interest to determine the effects of these additives on xylan-grown cultures. Although cell-bound xylanase activity increased when either PAA/PPA or ruminal fluid was ad...

The xylanolytic extremely thermophilic bacterium Caldicellulosiruptor owensensis provides a promising platform for xylan utilization. In the present study, two novel xylanolytic enzymes, GH10 endo-β-1,4-xylanase (Coxyn A) and GH39 β-1,4-xylosidase (Coxyl A) encoded in one gene cluster of C.owensensis were heterogeneously expressed and biochemically characterized. The optimum temperature of the ...