103302-04-1Relevant articles and documents
Two family 11 xylanases from Achaetomium sp. Xz-8 with high catalytic efficiency and application potentials in the brewing industry
Zhao, Liang,Meng, Kun,Bai, Yingguo,Shi, Pengjun,Huang, Huoqing,Luo, Huiying,Wang, Yaru,Yang, Peilong,Song, Wei,Yao, Bin
, p. 6880 - 6889 (2013)
This study identified two family-11 xylanase genes (xynC81 and xynC83) in Achaetomium sp. Xz-8, a thermophilic strain from a desert area with substantial xylanase activity, and successfully expressed them in Pichia pastoris. Their deduced amino acid sequences showed the highest identity of ≤90% to known fungal xylanases and of ≤62% with each other. The purified recombinant xylanases showed optimal activities at pH 5.5 and 60-65 C and exhibited stability over pH 5.0-10.0 and temperatures at 55 C and below. XynC81 had high catalytic efficiency (6082 mL/s/mg), and XynC83 was favorable for xylooligosaccharide production. Under simulated mashing conditions, combination of XynC83 and a commercial β-glucanase improved the filtration rate by 34.76%, which is much better than that of Novozymes Ultraflo (20.71%). XynC81 and XynC83 had a synergistic effect on viscosity reduction (7.08%), which is comparable with that of Ultraflo (8.47%). Thus, XynC81 and XynC83 represent good candidates for application in the brewing industry.
The impact of dilute sulfuric acid on the selectivity of xylooligomer depolymerization to monomers
Kumar, Rajeev,Wyman, Charles E.
, p. 290 - 300 (2008)
The disappearance of xylose and xylooligosaccharides with degrees of polymerization (DP) ranging from 2 to 5 was followed at 160 °C with sulfuric acid added to adjust the pH from near neutral to 1.45, and the impact on the yields of lower DP xylooligomers and xylose monomer was determined. In addition, the experimental data for the disappearance of these xylooligomers was kinetically modeled assuming first-order reaction kinetics for xylose degradation and xylooligomer hydrolysis to evaluate how the pH affected the selectivity of monomer formation from xylooligomers and direct oligomer degradation to unknown products. The yield of xylose from xylooligomers increased appreciably with increasing acid concentration but decreased with increasing xylooligomer DP at a given acid concentration, resulting in more acid being required to realize the same xylose yields for higher DP species. For example, the maximum xylose yields were 49.6%, 28.0%, 13.2% and 3.2% for DP values of 2, 3, 4, and 5, respectively, at pH 4.75. Kinetic modeling revealed that all the xylooligomers disappeared at a higher rate compared to xylose monomer and the disappearance rate constant increased with DP at all pH. The kinetics for lower DP oligomers of 2 and 3 showed that these species directly degrade to unknown compounds in the absence of acid. On the other hand, higher oligomers of DP 4 and 5 exhibited negligible losses to degradation products at all pH. Therefore, only xylooligomers of DP 2 and 3 were found to directly degrade to undesired products in the absence of acid, but more work is needed to determine how higher DP species behave. This study also revealed that the source of water and the material used for the construction of the reactor impacted xylose degradation kinetics.
Purification, characterization and mass spectrometric identification of two thermophilic xylanases from Sporotrichum thermophile
Vafiadi, Christina,Christakopoulos, Paul,Topakas, Evangelos
, p. 419 - 424 (2010)
Two xylanases were purified to electrophoretic homogeneity from the thermophilic fungus Sporotrichum thermophile grown in a submerged liquid culture using wheat straw as carbon source. The enzymes, StXyn1 and StXyn2, have molecular masses of 24 kDa and 48 kDa, respectively, and are optimally active at pH 5 and at 60 °C. Both enzymes displayed remarkable stability up to 50 °C for 1 h, exhibiting a half-life of 60 min (StXyn1) and 115 min (StXyn2) at 60 °C. Biochemical characterization of the two xylanases against poly- and oligosaccharides indicated that StXyn1 and StXyn2 hydrolytic profiles match those of xylanase family 11 and family 10, respectively. LC-MS/MS analysis provided peptide mass and sequence information that assisted the identification of the corresponding xylanase genes from the S. thermophile genome and the classification of the two purified StXyn1 and StXyn2 as a family GH11 and GH10 endo-1,4-β-xylanases, respectively.
β-xylosidase from Selenomonas ruminantium: Immobilization, stabilization, and application for xylooligosaccharide hydrolysis
Terrasan, César Rafael Fanchini,Aragon, Caio Casale,Masui, Douglas Chodi,Pessela, Benevides Costa,Fernandez-Lorente, Gloria,Carmona, Eleonora Cano,Guisan, Jose Manuel
, p. 161 - 171 (2016)
The tetrameric β-xylosidase from Selenomonas ruminantium is very stable in alkaline pH allowing it to easily immobilize by multipoint covalent attachments on highly activated glyoxyl agarose gels. Initial immobilization resulted only in slight stabilization in relation to the free enzyme, since involvement of all subunits was not achieved. Coating the catalyst with aldehyde-dextran or polyethylenimine, fully stabilized the quaternary structure of the enzyme rendering much more stabilization to the biocatalyst. The catalyst coated with polyethylenimine of molecular weight 1300 is the most stable one exhibiting an interesting half-life of more than 10 days at pH 5.0 and 50 °C, being, therefore, 240-fold more stable than free enzyme. Optimum activity was observed in the pH range 4.0–6.0 and at 55 °C. The catalyst retained its side activity against p-nitrophenyl α-l-arabinofuranoside and it was inhibited by xylose and glucose. Kinetic parameters with p-nitrophenyl β-d-xylopyranoside as substrate were Vmax 0.20 μmol.min?1 mg prot.?1, Km 0.45 mM, Kcat 0.82 s?1, and Kcat/Km 1.82 s?1 mM?1. Xylose release was observed from the hydrolysis of xylooligosaccharides with a decrease in the rate of xylose release by increasing substrate chain-length. Due to the high thermostability and the complete stability after five reuse cycles, the applicability of this biocatalyst in biotechnological processes, such as for the degradation of lignocellulosic biomass, is highly increased.
Characterization of a thermostable, specific GH10 xylanase from Caldicellulosiruptor bescii with high catalytic activity
An, Jiao,Xie, Yuan,Zhang, Yong,Tian, Dongsheng,Wang, Shuhao,Yang, Guangyu,Feng, Yan
, p. 13 - 20 (2015)
Xylanase (EC 3.2.1.8) is one of the most important enzymes for the biodegradation of xylan. Since many industrial processes utilizing xylanase are operated at elevated temperatures, thermostable xylanases are highly desirable. In the present study, xyn10B gene from thermophilic bacterium Caldicellulosiruptor bescii that encodes a glycoside hydrolase (GH) family 10 xylanase was overexpressed in Escherichia coli and systematically characterized. CbXyn10B exhibited optimal activity at pH 7.2 and 70 °C. It had a half-life of about 7.7 h at 60 °C, and retained over 85% of maximal activity after incubation at pH 4.0-12.0. The activity of this xylanase was not affected by most divalent cations, but inhibited by Fe3+ and Zn2+. CbXyn10B exhibited high activity on beech wood xylan, oat spelt xylan, and birch wood xylan, with specific activities of about 450 U mg-1. Compared with other GH10 xylanases, CbXyn10B was highly specific for xylan and showed low catalytic efficiency toward sodium carboxymethyl cellulose and p-nitrophenyl-β-d-xylopyranoside. HPLC analysis of the products released from xylo-oligosaccharides and xylan revealed that xylobiose was the predominant hydrolytic product. The action mode of the enzyme was studied by product analysis, homology modeling and molecular docking to gain an insight into the structural basis for its substrate recognition mechanism.
Characterization of Two New Endo-β-1,4-xylanases from Eupenicillium parvum 4–14 and Their Applications for Production of Feruloylated Oligosaccharides
Long, Liangkun,Xu, Meijuan,Shi, Yuexin,Lin, Qunying,Wang, Jing,Ding, Shaojun
, p. 816 - 833 (2018/05/15)
Two new endo-1,4-beta-xylanases encoding genes EpXyn1 and EpXyn3 were isolated from mesophilic fungus Eupenicillium parvum 4–14. Based on analysis of catalytic domain and phylogenetic trees, the xylanases EpXYN1 (404 aa) and EpXYN3 (220 aa) belong to glycoside hydrolase (GH) family 10 and 11, respectively. Both EpXYN1 and EpXYN3 were successfully expressed in Pichia pastoris and the recombinant enzymes were characterized using beechwood xylan, birchwood xylan, or oat spelt xylan as substrates, respectively. The optimum temperatures and pH values were 75?°C and 5.5 for EpXYN1, and 55?°C and 5.0 for EpXYN3. EpXYN1 exhibited a high stability at high temperature (65?°C) or at pH values from 8 to 10. EpXYN3 kept over 80% enzymatic activity after treatment at pH values from 3 to 10. The specific activities of EpXYN1 and EpXYN3 were 384.42 and 214.20?U/mg?using beechwood xylan as substrate, respectively. EpXYN1 showed lower Km values and higher specific activities toward different xylans compared to EpXYN3. Thin-layer chromatography analysis indicated that the hydrolysis profiles of xylans or xylo-oligosacharides were different by EpXYN1and EpXYN3. EpXYN3 had a higher efficiency than EpXYN1 in production of feruloylated oligosaccharides (FOs) from de-starched wheat bran. The maximum levels of FOs released by EpXYN1 and EpXYN3 were 11.1 and 14.4?μmol/g, respectively. In conclusion, the two xylanases are potential candidates for various industrial applications.
A novel thermostable cellulase free xylanase stable in broad range of pH from Streptomyces sp. CS428
Pradeep,Choi, Yun Hee,Choi, Yoon Seok,Seong, Chi Nam,Cho, Seung Sik,Lee, Hyo Jeong,Yoo, Jin Cheol
, p. 1188 - 1196 (2013/09/02)
A cellulase free thermostable xylanase from Streptomyces sp. CS428 was isolated from a Korean soil sample, purified by single-step chromatography, and biochemically characterized. The extracellular xylanase was purified 26 fold with a 55% yield by CM Trisacryl cation exchange chromatography. The molecular mass of the enzyme (Xyn428) was approximately 37 kDa. Xyn428 was found to be stable over a broad pH range (4 to ~13.6) and to 50 C and have an optimum temperature of 80 C. Xyn428 had Km and Vmax values of 102.3 ± 1.2 mg/mL and 3225.4 ± 15 mmol/min mg, respectively, when beechwood xylan was used as substrate. N-terminal sequence of Xyn428 was INRTDHNENSYLEIHNNEAR. CS428 was grown on different agro waste xylan and produced 4197.1 U/mL of xylanase activity in 36 h of cultivation in wheat bran without supplements. Xyn428 activity was inhibited by Tris salt at concentrations above 20 mM, and produced xylose and xylobiose as major products. It was found to degrade agro waste materials by small unit of enzyme (20 U/g) as shown by electron microscopy. As being simple in purification, thermo tolerant, pH stability in broad range and ability to produce xylooligosaccharides show that Xyn428 has potential applications in industries as a biobleaching agent and for xylooligosaccharides production.
A novel thermoacidophilic family 10 xylanase from Penicillium pinophilum C1
Cai, Hongying,Shi, Pengjun,Bai, Yingguo,Huang, Huoqing,Yuan, Tiezheng,Yang, Peilong,Luo, Huiying,Meng, Kun,Yao, Bin
experimental part, p. 2341 - 2346 (2012/06/05)
A novel endo-β-1,4-xylanase gene (xyn10C1) was cloned from Penicillium pinophilum C1 and overexpressed in Pichia pastoris. The 1071-bp full-length gene encodes a 356-residue polypeptide containing the catalytic domain of glycoside hydrolase 10. Deduced XYN10C1 shares highest amino acid sequence identity of 49.3% with a putative xylanase from Glomeella graminicola M1.001. Purified recombinant XYN10C1 showed maximal activity at pH 4.0-5.5 and 75 °C, exhibited good adaptability to broad acidic pH and temperature ranges (>69.0% activity at pH 2.5-6.5; and >91.0% activity at 70-80 °C and 22.2% even at 90 °C), and was highly stable at pH 2.0-7.0 for 1 h at 37 °C. The specific activity, Km and Vmax values for birchwood xylan and soluble wheat arabinoxylan were 100.7 and 137.4 U/mg, 4.3 and 6.9 mg/ml, and 195.4 and 209.3 μmol/min/mg, respectively. The enzyme was strongly resistant to most metal ions and proteases (pepsin and trypsin). Under simulated mashing conditions, addition of XYN10C1 (80 U) to the brewery mash (12.5 g in 50 ml system) significantly increased the filtration rate by 26.7% and reduced the viscosity by 9.8%, respectively. All these favorable enzymatic properties make XYN10C1 attractive for potential applications in the food and animal feed industries.
Molecular cloning and characterization of a novel thermostable xylanase from Paenibacillus campinasensis BL11
Ko, Chun-Han,Tsai, Chung-Hung,Tu, Jenn,Lee, Hang-Yi,Ku, Lan-Ting,Kuo, Pei-An,Lai, Yiu-Kay
supporting information; experimental part, p. 1638 - 1644 (2011/12/03)
An open reading frame (XylX) with 1131 nucleotides from Paenibacillus campinasensis BL11 was cloned and expressed in E. coli. It encodes a family 11 endoxylanase, designated as XylX, of 41kDa. The homology of the amino acid sequence deduced from XylX is only 73% identical to the next closest sequence. XylX contains a family 11 catalytic domain of the glycoside hydrolase and a family 6 cellulose-binding module. The recombinant xylanase was fused to a His-tag for affinity purification. The XylX activity was 2392IU/mg, with a Km of 6.78mg/ml and a Vmax of 4953mol/min/mg under optimal conditions (pH 7, 60°C). At pH 11, 60°C, the activity was still as high as 517IU/mg. Xylanase activities at 60°C under pH 5 to pH 9 remained at more than 69.4% of the initial activity level for 8h. The addition of Hg2+ at 5mM almost completely inhibited xylanase activity, whereas the addition of tris-(2-carboxyethyl)-phosphine (TCEP) and 2-mercaptoethanol stimulated xylanase activity. No relative activities for Avicel, CMC and d-(+)-cellobiose were found. Xylotriose constitutes the majority of the hydrolyzed products from oat spelt and birchwood xylan. Broad pH and temperature stability shows its application potentials for biomass conversion, food and pulp/paper industries.