Oat Spelt Xylan Research Articles

Heterologous expression of thermostable acetylxylan esterase gene from Thermobifida fusca and its synergistic action with xylanase for the production of xylooligosaccharides

The axe gene which encodes an acetylxylan esterase from Thermobifida fusca NTU22, was cloned, sequenced and expressed in Escherichia coli. The gene consists of 786 base pairs and encodes a protein of 262 amino acids. The deduced amino acid sequence of the acetylxylan esterase axe exhibited a high degree of similarity with BTA-hydrolase from T. fusca DSM43793, esterase from Thermobifida alba and lipase from Streptomyces albus. The optimal pH and temperature of the purified esterase were 7.5 and 60 °C, respectively. Cooperative enzymatic treatment of oat-spelt xylan by transformant xylanase and acetylxylan esterase significantly increased the xylooligosaccharides production compared with the xylanase or acetylxylan esterase action alone. The synergy of transformant acetylxylan esterase and xylanase cannot increase the production of reducing sugars from lignocellulolytic substrate, bagasse.

Utilization of deoiled Jatropha curcas seed cake for production of xylanase from thermophilic Scytalidium thermophilum

Jatropha curcas is a major biodiesel crop. Large amount of deoiled cake is generated as by-product during biodiesel production from its seeds. Deoiled J. curcas seed cake was assessed as substrate for the production of xylanase from thermophilic fungus Scytalidium thermophilum by solid-state fermentation. The seed cake was efficiently utilized by S. thermophilum for its growth during which it produced good amount of heat stable extracellular xylanase. The solid-state fermentation conditions were optimized for maximum xylanase production. Under the optimized conditions viz. deoiled seed cake supplemented with 1% oat-spelt xylan, adjusted to pH 9.0, moisture content 1:3 w/v, inoculated with 1×10(6) spores per 5 g cake and incubated at 45 °C, 1455 U xylanase/g deoiled seed cake was obtained. The xylanase was useful in biobleaching of paper pulp. Solid-state fermentation of deoiled cake appears a potentially viable approach for its effective utilization.

Characterization of a thermostable xylanase from an alkaliphilic Bacillus sp.

A xylanase gene (xyn10) from alkaliphilic Bacillus sp. N16-5 was cloned and expressed in Pichia pastoris. The deduced amino acid sequence has 85% identity with xylanase xyn10A from B. halodurans and contains two potential N-glycosylation sites. The glycosylated Xyn10 with MW 48kDa can hydrolyze birchwood and oatspelt xylan. The enzyme had optimum activity at pH 7 and 70°C, with the specific activity of 92.5U/mg. The Xyn10 retained over 90% residual activity at 60°C for 30min but lost all activity at 80°C over 15min. Most tested ions showed no or slight inhibition effects on enzyme activity.

Directed evolution of a mesophilic fungal xylanase by fusion of a thermophilic bacterial carbohydrate-binding module

Bacterial GH10 xylanase usually contains carbohydrate-binding module (CBM) that binds to insoluble xylan. Differing from GH10 xylanase, we isolated a fungal GH11 xylanase containing a single catalytic domain from Aspergilus niger (XYN). The thermophilic CBM from Thermotoga maritima (TmCBM9-1_2) might increase the mesophilic XYN's thermo-activity and catalytic efficiency on insoluble xylan, we fused it with the TmCBM9-1_2 behaving as “hand” to grasp xylan actively. The chimeric xylanase XYN-TmCBM9-1_2 exhibited an optimal activity at pH4.2 and 49 °C, 2 °C higher than the thermo-activity of XYN. The chimeric xylanase's activity was 970.1 ± 5.8 U/mg on insoluble oat-spelt xylan, 4.2-fold of that on soluble birchwood xylan (228.1 ± 1.1 U/mg). In contrast, the XYN's activity was 226.9 ± 1.2 U/mg on insoluble oat-spelt xylan, only 40% of that on soluble birchwood xylan (567.2 ± 3.0 U/mg). Fusing with the TmCBM9-1_2 increased the XYN's property, indicating that we can direct to evolve a molecule's function through fusing domains of bacteria and fungi.

Influence of transposition and insertion of additional binding domain on expression and characteristics of xylanase C of Clostridium thermocellum

Clostridium thermocellum encodes a xylanase gene ( xynC) which is the major component of its cellulosome. XynC is a multidomain enzyme comprising of a substrate binding domain at the N-terminal followed by the catalytic domain and a dockerin domain. To study the influence of binding domain on activity, stability and expression of the enzyme the protein with the binding domain at C-terminal (XynC-CB), and the one with the binding domain at both N- and C-terminal (XynC-BCB) were expressed in E. coli. Recombinant plasmids, pXynC-CB and pXynC-BCB were constructed by inserting the corresponding gene in pET22b(+). XynC-CB and XynC-BCB were expressed at levels around 30% and 33% of the total E. coli cell proteins, respectively, while losing 40% and 20% of their activities at 70 °C for 120 min, respectively. The specific activities of XynC-CB , XynC-BCB were 76 and 98 U mg −1, while the activities on equimolar basis were 4410 and 7450 U μM −1 against birchwood xylan, respectively. Their overall activities produced in the culture were 3660 and 5430 U L −1 OD 600 −1. Substrate binding studies showed that in case of XynC-C 51% of the activity remained unbound to birchwood xylan, whereas in the cases of XynC-BC, XynC-CB and XynC-BCB the activities left unbound were 33%, 32% and 12%, respectively, under the assay conditions used. Similar binding values were obtained in the case of oat spelt xylan. K m values for XynC-CB and XynC-BCB against birchwood xylan were found to be 3.1 and 1.47 mg ml −1, respectively. Thus addition of a second carbohydrate binding domain at the C-terminal of the catalytic domain enhances activity, substrate affinity as well as thermostability.

Xylanases of anaerobic fungus Anaeromyces mucronatus

The anaerobic fungus Anaeromyces mucronatus KF8 grown in batch culture on M10 medium with rumen fluid and microcrystalline cellulose as carbon source produced a broad range of enzymes requisite for degradation of plant structural and storage saccharides including cellulase, endoglucanase, xylanase, alpha-xylosidase, beta-xylosidase, alpha-glucosidase, beta-glucosidase, beta-galactosidase, mannosidase, cellobiohydrolase, amylase, laminarinase, pectinase and pectate lyase. These enzymes were detected in both the intra- and extracellular fractions, but production into the medium was prevalent with the exception of intracellular beta-xylosidase, chitinases, N-acetylglucosaminidase, and lipase. Xylanase activity was predominant among the polysaccharide hydrolases. Extracellular production of xylanase was stimulated by the presence of cellobiose and oat spelt xylan. Zymogram of xylanases of strain KF8 grown on different carbon sources revealed several isoforms of xylanases with approximate molar masses ranging from 26 to 130 kDa.

Identification and characterization of a novel xylanase derived from a rice straw degrading enrichment culture

A metagenomic library containing ca. 3.06 x 10(8) bp insert DNA was constructed from a rice straw degrading enrichment culture. A xylanase gene, umxyn10A, was cloned by screening the library for xylanase activity. The encoded enzyme Umxyn10A showed 58% identity and 73% similarity with a xylanase from Thermobifida fusca YX. Sequence analyses showed that Umxyn10A contained a glycosyl hydrolase family 10 catalytic domain. The gene was expressed in Escherichia coli, and the recombinant enzyme was purified and characterized biochemically. Recombinant Umxyn10A was highly active toward xylan. However, the purified enzyme could slightly hydrolyze beta-1,3/4-glucan and beta-1,3/6-glucan. Umxyn10A displayed maximal activity toward oat spelt xylan at a high temperature (75 degrees C) and weak acidity (pH 6.5). The K( m ) and V (max) of Umxyn10A toward oat spelt xylan were 3.2 mg ml(-1) and 0.22 mmol min(-1) mg(-1) and were 2.7 mg ml(-1) and 1.0 mmol min(-1) mg(-1) against birchwood xylan, respectively. Metal ions did not appear to be required for the catalytic activity of this enzyme. The enzyme Umxyn10A could efficiently hydrolyze birchwood xylan to release xylobiose as the major product and a negligible amount of xylose. The xylanase identified in this work may have potential application in producing xylobiose from xylan.

Purification and characterization studies of a thermostable β-xylanase from Aspergillus awamori

This study presents data on the production, purification, and properties of a thermostable β-xylanase produced by an Aspergillus awamori 2B.361 U2/1 submerged culture using wheat bran as carbon source. Fractionation of the culture filtrate by membrane ultrafiltration followed by Sephacryl S-200 and Q-Sepharose chromatography allowed for the isolation of a homogeneous xylanase (PXII-1), which was 32.87 kDa according to MS analysis. The enzyme-specific activity towards soluble oat spelt xylan, which was found to be 490 IU/mg under optimum reaction conditions (50°C and pH 5.0-5.5), was 17-fold higher than that measured in the culture supernatant. Xylan reaction products were identified as xylobiose, xylotriose, and xylotetraose. K (m) values (mg ml(-1)) for soluble oat spelt and birchwood xylan were 11.8 and 9.45, respectively. Although PXII-1 showed 85% activity retention upon incubation at 50 °C and pH 5.0 for 20 days, incubation at pH 7.0 resulted in 50% activity loss within 3 days. PXII-1 stability at pH 7.0 was improved in the presence of 20 mM cysteine, which allowed for 85% activity retention for 25 days. This study on the production in high yields of a remarkably thermostable xylanase is of significance due to the central role that this class of biocatalyst shares, along with cellulases, for the much needed enzymatic hydrolysis of biomass. Furthermore, stable xylanases are important for the manufacture of paper, animal feed, and xylooligosaccharides.

Characterization of Xyn10A, a highly active xylanase from the human gut bacterium Bacteroides xylanisolvens XB1A

A xylanase gene xyn10A was isolated from the human gut bacterium Bacteroides xylanisolvens XB1A and the gene product was characterized. Xyn10A is a 40-kDa xylanase composed of a glycoside hydrolase family 10 catalytic domain with a signal peptide. A recombinant His-tagged Xyn10A was produced in Escherichia coli and purified. It was active on oat spelt and birchwood xylans and on wheat arabinoxylans. It cleaved xylotetraose, xylopentaose, and xylohexaose but not xylobiose, clearly indicating that Xyn10A is a xylanase. Surprisingly, it showed a low activity against carboxymethylcellulose but no activity at all against aryl-cellobioside and cellooligosaccharides. The enzyme exhibited K (m) and V (max) of 1.6 mg ml(-1) and 118 micromol min(-1) mg(-1) on oat spelt xylan, and its optimal temperature and pH for activity were 37 degrees C and pH 6.0, respectively. Its catalytic properties (k (cat)/K (m) = 3,300 ml mg(-1) min(-1)) suggested that Xyn10A is one of the most active GH10 xylanase described to date. Phylogenetic analyses showed that Xyn10A was closely related to other GH10 xylanases from human Bacteroides. The xyn10A gene was expressed in B. xylanisolvens XB1A cultured with glucose, xylose or xylans, and the protein was associated with the cells. Xyn10A is the first family 10 xylanase characterized from B. xylanisolvens XB1A.

A novel xylanase, XynA4-2, from thermoacidophilic Alicyclobacillus sp. A4 with potential applications in the brewing industry

A xylanase gene, xynA4-2, was obtained from the genome sequence of thermoacidophilic Alicyclobacillus sp. A4 and expressed in Escherichia coli BL21 (DE3). xynA4-2 encodes a mature protein of 411 residues with a calculated molecular weight of 46.8 kDa. Based on the amino acid sequence similarities (highest identity of 61%), the enzyme was confined into glycoside hydrolase family 10. The purified recombinant XynA4-2 exhibited maximum activity at pH 6.2 and 55°C. The enzyme was stable over a broad pH range, retaining more than 90% of the original activity at pH 5.8–12.0, 37°C for 1 h. The substrate specificity of XynA4-2 was relatively narrow, exhibiting 100, 93, and 35% of the relative activity towards birchwood xylan, oat spelt xylan, and wheat arabinoxylan, respectively. Supplementation of XynA4-2 to mash caused the reduction of mash filtration rate (5.6%) and viscosity (4.0%). When combined with the commercial glucanase from Sunson, higher reduction was detected in the filtration rate (12.0%) and viscosity (17.2%). These favorable properties make XynA4-2 a good candidate in the brewing industry.

A Highly Thermostable Alkaline Cellulase-Free Xylanase from Thermoalkalophilic Bacillus sp. JB 99 Suitable for Paper and Pulp Industry: Purification and Characterization

A highly thermostable alkaline xylanase was purified to homogeneity from culture supernatant of Bacillus sp. JB 99 using DEAE-Sepharose and Sephadex G-100 gel filtration with 25.7-fold increase in activity and 43.5% recovery. The molecular weight of the purified xylanase was found to be 20 kDA by SDS-PAGE and zymogram analysis. The enzyme was optimally active at 70 °C, pH 8.0 and stable over pH range of 6.0-10.0.The relative activity at 9.0 and 10.0 were 90% and 85% of that of pH 8.0, respectively. The enzyme showed high thermal stability at 60 °C with 95% of its activity after 5 h. The K (m) and V (max) of enzyme for oat spelt xylan were 4.8 mg/ml and 218.6 µM min(-1) mg(-1), respectively. Analysis of N-terminal amino acid sequence revealed that the xylanase belongs to glycosyl hydrolase family 11 from thermoalkalophilic Bacillus sp. with basic pI. Substrate specificity showed a high activity on xylan-containing substrate and cellulase-free nature. The hydrolyzed product pattern of oat spelt xylan on thin-layer chromatography suggested xylanase as an endoxylanase. Due to these properties, xylanase from Bacillus sp. JB 99 was found to be highly compatible for paper and pulp industry.

Paenibacillus sp. Strain E18 Bifunctional Xylanase-Glucanase with a Single Catalytic Domain

Xylanases are utilized in a variety of industries for the breakdown of plant materials. Most native and engineered bifunctional/multifunctional xylanases have separate catalytic domains within the same polypeptide chain. Here we report a new bifunctional xylanase (XynBE18) produced by Paenibacillus sp. E18 with xylanase and beta-1,3-1,4-glucanase activities derived from the same active center by substrate competition assays and site-directed mutagenesis of xylanase catalytic Glu residues (E129A and E236A). The gene consists of 981 bp, encodes 327 amino acids, and comprises only one catalytic domain that is highly homologous to the glycoside hydrolase family 10 xylanase catalytic domain. Recombinant XynBE18 purified from Escherichia coli BL21(DE3) showed specificity toward oat spelt xylan and birchwood xylan and beta-1,3-1,4-glucan (barley beta-glucan and lichenin). Homology modeling and molecular dynamic simulation were used to explore structure differences between XynBE18 and the monofunctional xylanase XynE2, which has enzymatic properties similar to those of XynBE18 but does not hydrolyze beta-1,3-1,4-glucan. The cleft containing the active site of XynBE18 is larger than that of XynE2, suggesting that XynBE18 is able to bind larger substrates such as barley beta-glucan and lichenin. Further molecular docking studies revealed that XynBE18 can accommodate xylan and beta-1,3-1,4-glucan, but XynE2 is only accessible to xylan. These results indicate a previously unidentified structure-function relationship for substrate specificities among family 10 xylanases.

Biocatalytic approach for the utilization of hemicellulose for ethanol production from agricultural residue using thermostable xylanase and thermotolerant yeast

A hydrolysis of 62% and 50% for OSX (Oat spelt xylan) and WBH (Wheat bran hemicellulose) were obtained in 36 h and 48 h using Accellerase™ 1000 at 50 °C wherein thermostable xylanase from alkalothermophilic Thermomonospora sp. yielded 67% (OSX) in 3 h and 58% (WBH) in 24 h at 60 °C, favouring a reduction in process time and enzyme dosage. The rate of hydrolysis with thermostable xylanase was increased by 20% with the addition of nonionic surfactant tween 80 or biosurfactant sophorolipid. The simultaneous saccharification and fermentation (SSF) of OSX and WBH using thermostable xylanase and D. hansenii in batch cultures produced 9.1 g/L and 9.5 g/L of ethanol, respectively and had a shorter overall process time than the separate hydrolysis and fermentation (SHF). The immobilized yeast cells in Ca-alginate matrix produced ethanol with a yield of 0.46 g/g from hemicellulosic hydrolysates and were reused six times with 100% fermentation efficiency.

Cell-associated β-xylosidase from Aureobasidium pullulans ATCC 20524: Purification, properties, and characterization of the encoding gene

A cell-associated enzyme exhibiting beta-xylosidase activity was purified from the cell extract of the dimorphic fungus, Aureobasidium pullulans strain ATCC 20524, grown on oat spelt xylan. The purified enzyme was homogeneous as judged by SDS-PAGE, which showed an apparent M(r) of 88.5 kDa. beta-Xylosidase activity was optimal at pH 3.5 and 70 degrees C. The enzyme exhibited apparent K(m) and V(max) values of 3.5 mM and 263 micromol/mg/min, respectively, for p-nitrophenyl-beta-d-xylopyranoside. The enzyme also showed some alpha-l-arabinofuranosidase activity. Southern blot analysis indicated that the beta-xylosidase gene (xylI) was present as a single copy in the genome. The genomic DNA and cDNA encoding this protein were cloned and sequenced. The open reading frame of 2415 bp was interrupted by two introns of 54 and 52 bp, and it encoded a presumed signal peptide of 20 residues and a mature protein of 785 residues with a calculated M(r) of 85,045 Da and a deduced isoelectric point of 4.57. The protein was N-glycosylated and possessed 16 potential N-glycosylation sites. Two distinct transcription start points of the xylI gene were present at nt -32 (A) and -26 (A) from the start codon. The xylI cDNA was functionally expressed in the yeast Pichia pastoris. The deduced amino acid sequence of the xylI gene product was 49% identical to the Talaromyces emersonii beta-xylosidase Bxl1, which belongs to the glycoside hydrolase family 3.

A xylanase with broad pH and temperature adaptability from Streptomyces megasporus DSM 41476, and its potential application in brewing industry

A xylanase gene, xynAM6, was isolated from the genomic DNA library of Streptomyces megasporus DSM 41476 using colony PCR screening method. The 1440-bp full-length gene encodes a 479-amino acid peptide consisting of a putative signal peptide of 36 residues, a family 10 glycoside hydrolase domain and a family 2 carbohydrate-binding module. The mature peptide of xynAM6 was successfully expressed in Pichia pastoris GS115. The optimal pH and temperature were pH 5.5 and 70°C, respectively. The enzyme showed broad temperature adaptability (>60% of the maximum activity at 50–80°C), had good thermostability at 60°C and 70°C, remained stable at pH 4.0–11.0, and was resistant to most proteases. The Km and Vmax values for oat spelt xylan were 1.68mgml−1 and 436.76μmolmin−1mg−1, respectively, and 2.33mgml−1 and 406.93μmolmin−1mg−1 for birchwood xylan, respectively. The hydrolysis products of XYNAM6 were mainly xylose and xylobiose. Addition of XYNAM6 (80U) to the brewery mash significantly reduced the filtration rate and viscosity by 36.33% and 35.51%, respectively. These favorable properties probably make XYNAM6 a good candidate for application in brewing industry.

Molecular cloning and characterization of the novel acidic xylanase XYLD from Bispora sp. MEY-1 that is homologous to family 30 glycosyl hydrolases

We cloned and sequenced a xylanase gene named xylD from the acidophilic fungus Bispora sp. MEY-1 and expressed the gene in Pichia pastoris. The 1,422-bp full-length complementary DNA fragment encoded a 457-amino acid xylanase with a calculated molecular mass of 49.8 kDa. The mature protein of XYLD showed high sequence similarity to both glycosyl hydrolase (GH) families 5 and 30 but was more homologous to members of GH 30 based on phylogenetic analysis. XYLD shared the highest identity (49.9%) with a putative endo-1,6-beta-D-glucanase from Talaromyces stipitatus and exhibited 21.1% identity and 34.3% similarity to the well-characterized GH family 5 xylanase from Erwinia chrysanthemi. Purified recombinant XYLD showed maximal activity at pH 3.0 and 60 degrees C, maintained more than 60% of maximal activity when assayed at pH 1.5-4.0, and had good thermal stability at 60 degrees C and remained stable at pH 1.0-6.0. The enzyme activity was enhanced in the presence of Ni(2+) and beta-mercaptoethanol and inhibited by some metal irons (Hg(2+), Cu(2+), Pb(2+), Mn(2+), Li(+), and Fe(3+)) and sodium dodecyl sulfate. The specific activity of XYLD for beechwood xylan, birchwood xylan, 4-O-methyl-D-glucuronoxylan, and oat spelt xylan was 2,463, 2,144, 2,020, and 1,429 U mg(-1), respectively. The apparent K (m) and V (max) values for beechwood xylan were 5.6 mg ml(-1) and 3,622 micromol min(-1) mg(-1), respectively. The hydrolysis products of different xylans were mainly xylose and xylobiose.

Functional characterisation of a recombinant xylanase fromPichia pastorisand effect of the enzyme on nutrient digestibility in weaned pigs

The xyn2 gene of a filamentous mesophilic fungus, Trichoderma reesei, coding xylanase 2 (Xyn2) was previously expressed in Pichia pastoris. In the present study, the recombinant Xyn2 was prepared from a 15 litre fermenter, and subsequently characterised. It has been confirmed to have a molecular mass of 21 kDa, an optimal pH of 6.0 and an optimal temperature of 60 degrees C. When tested using oat-spelt xylan, it showed a Km and catalytic rate constant (kcat) of 1.1 mg/ml and 512.4/s, respectively. Analysis of the products from oat-spelt xylan degradation confirmed that the enzyme was an endoxylanase with xylotriose and xylobiose as the main degradation products. The unprocessed Xyn2 was supplemented to a xylan-containing diet to determine its influences on performance and nutrient digestibilities by weaned pigs. Results showed that the average body-weight gain increased 16.9 % when piglets received Xyn2 at a concentration of 500 U/kg diet. There also was a positive (0.05 < P < 0.10) effect on the digestibility values of crude protein, ash, Ca and acid-detergent fibre with Xyn2 supplementation. The potential benefits of Xyn2 in the nutrition of weaned pigs should make it an alternative applicant for industrial xylanase production.

Dietary fibre degradation and fermentation by two xylanolytic bacteria Bacteroides xylanisolvens XB1A T and Roseburia intestinalis XB6B4 from the human intestine

To characterize fibre degradation, colonization and fermentation, and xylanase activity of two xylanolytic bacteria Bacteroides xylanisolvens XB1A(T) and Roseburia intestinalis XB6B4 from the human colon. The bacteria grew well on all the substrates chosen to represent dietary fibres: wheat and corn bran, pea, cabbage and leek fibres, and also on purified xylans. Roseburia intestinalis colonized the substrates more efficiently than Bact. xylanisolvens. For the two bacteria, 80-99% of the total xylanase activity was associated with the cells whatever the substrate and time of growth. Optimal specific activities of cells were obtained on oat spelt xylan; they were higher than those previously measured for xylanolytic bacteria from the human gut. Roseburia intestinalis produced high molecular mass xylanases (100-70 kDa), while Bact. xylanisolvens produced lower molecular mass enzymes, including a cell-associated xylanase of 37 kDa. The two bacteria display very high xylanolytic activity on the different substrates. Differences were observed on substrate attachment and enzyme systems, suggesting that the two species occupy different niches within the gut microbiota. This study characterizes xylan degradation by two major species of the human intestine.

Purification and characterization of a high-thermostable &lt;i&gt;β&lt;/i&gt;-xylanase from newly isolated &lt;i&gt;Thermomyces lanuginosus&lt;/i&gt; THKU-49

Highly thermostable β-xylanase produced by newly isolated Thermomyces lanuginosus THKU-49 strain was purified in a four-step procedure involving ammonium sulfate precipitation and subsequent separation on a DEAE-Sepharose fast flow column, hydroxylapatite column, and Sephadex G-100 column, respectively. The enzyme purified to homogeneity had a specific activity of 552 U/mg protein and a molecular weight of 24.9 kDa. The optimal temperature of the purified xylanase was 70°C, and it was stable at temperatures up to 60°C at pH 6.0; the optimal pH was 5.0–7.0, and it was stable in the pH range 3.5–8.0 at 4°C. Xylanase activity was inhibited by Mn2+, Sn2+, and ethylenediaminetetraacetic acid. The xylanase showed a high activity towards soluble oat spelt xylan, but it exhibited low activity towards insoluble oat spelt xylan; no activity was found to carboxymethylcellulose, avicel, filter paper, locust bean gum, cassava starch, and p-nitrophenyl β-D-xylopyranoside. The apparent Km value of the xylanase on soluble oat spelt xylan and insoluble oat spelt xylan was 7.3 ± 0.236 and 60.2 ± 6.788 mg/ml, respectively. Thin-layer chromatography analysis showed that the xylanase hydrolyzed oat spelt xylan to yield mainly xylobiose and xylose as end products, but that it could not release xylose from the substrate xylobiose, suggesting that it is an endo-xylanase.

Production of xylooligosaccharides from enzymatic hydrolysis of xylan by white-rot fungi Pleurotus

Hemicellulose consists of non-cellulosic polysaccharides, with xylans and mannans as their main examples. In nature, xylan can be first degraded to xylooligosaccharides and finally to xylose by certain microorganisms. White-rot fungi basidiomycetes Pleurotus sp. BCCB068 and Pleurotus tailandia were used to degrade oat-spelts xylan under submerged fermentation for a period of 40 days. The study obtained activities of endo-1,4-β-xylanase and β-xylosidase and determination of xylan products by degradation. The fungi reached significant levels of xylan degradation by Pleurotus sp. BCCB068 (75.1%) and P. tailandia (73.4%), following formations of xylooligosaccharides and sugar monomers. These Pleurotus strains proved to be a feasible alternative for biotechnological processes related to degradation of hemicellulose sources