Molecular Characterization of Xylobiose- and Xylopentaose-Producing β-1,4-Endoxylanase SCO5931 from Streptomyces coelicolor A3(2)

Abstract

Streptomyces coelicolor A3(2) sco5931 gene was predicted to encode a putative xylanase A, a 477 amino acid protein belonging to glycoside hydrolase family 10. The entire sco5931 coding region was cloned and overexpressed in Streptomyces lividans TK24. Mature SCO5931 protein comprising 436 amino acids (47 kDa) was purified by single-step gel filtration chromatography from culture broth after ammonium sulfate precipitation, with 25.8-fold purification and yield of 30.6 %. The purified protein displayed a pronounced activity toward beechwood xylan as a substrate, but no activity was detected toward carboxymethylcellulose, Avicel, galactan, barley β-glucan, and xyloglucan, demonstrating that SCO5931 is a substrate-specific xylanase. Optimal xylanase activity was observed at 60 °C and pH 6.0. The addition of metal ions or EDTA did not affect the xylanase activity, while 4 mM MnCl2 severely inhibited the enzyme, reducing its activity by 87 %. Kinetic parameters of SCO5931 toward beechwood xylan were determined (K m = 0.24 mg/mL, V max = 6.86 μM/min). Thin layer chromatography and mass spectrometry analyses of the beechwood xylan SCO5931 hydrolysis products were conducted. Product masses corresponded to sodium adducts of xylobiose (m/z 305.24) and xylopentaose (m/z 701.59), indicating that SCO5931 specifically cleaves the β-1,4 linkage of xylan to yield xylobiose and xylopentaose.

Biochemical Characterization of Xylanases from Streptomyces sp. B6 and Their Application in the Xylooligosaccharide Production from Viscose Fiber Production Waste

“…TN119 46 but also higher than reported xynlanase from Paenibacillus barergoltziii, 9 Geobacillus thermoleorans, 24 Aspergillus niger, 50 and Aspergillus f lavus, 29 although it is less active than xylanases of Streptomyces sp. CS802, 21 Streptomyces coelicolor A3 (2), 51 and Streptomyces rameus L2001. 43 Interestingly, XynST10 and XynST11 also showed relatively high activity with HCAWS as substrate, suggesting their tolerance to the harsh conditions (high salt, various metal ions, and chemical residues).…”

Characterization of a novel xylanase from Aspergillus flavus with the unique properties in production of xylooligosaccharides

“…They have come to the forefront of investigations due to their variety of health benefiting effects such as acting as prebiotics, lowering cholesterol level, improving the biological availability of calcium, etc. They also exhibit wide range of biologic activities including antioxidant, anti‐inflammatory, immunomodulatory, and anti‐cancer . XOs are mainly produced by chemical methods, enzymatic degradation, or combined chemical‐enzymatic method from the xylan‐rich hemicelluloses .…”

“…As per the available literature, the majority of reported xylanases usually hydrolyze xylans to mainly yield XOs with a low DP (DP ≤ 3) or a mixture of XOs with DP from 2 to 7 . Nevertheless, it is hard to reach any report about the xylanases with the unique hydrolytic property to yield X2 and X5 as the end products . In order to develop endo‐xylanases with such unique hydrolytic property, the distinctive resources of microorganism for this novel xylanase should be excavated and evaluated.…”

Improvement in catalytic activity and thermostability of a GH10 xylanase and its synergistic degradation of biomass with cellulase

“…Common approaches involve mining new genetic resources from extreme environments, engineering the enzymes, and optimizing their application [8, 9]. Several xylanases from Aspergillus fumigatus R1 [10], Streptomyces coelicolor A3 [11], Aspergillus niger [12], and Bispora sp. MEY-1 [13] have high catalytic activities of 18,000 to 38,000 U/mg.…”