Purification and characterization of a new xylanase with excellent stability from Aspergillus flavus and its application in hydrolyzing pretreated corncobs

• Published in: Protein expression and purification Vol. 154; pp. 91 - 97
• Main Authors: Chen, Zhou, Zaky, Ahmed A., Liu, Yangliu, Chen, Yaoyao, Liu, Lu, Li, Siting, Jia, Yingmin
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2019
• Subjects: Aspergillus flavus; Aspergillus flavus - enzymology; Characterization; Corncobs; Endo-1,4-beta Xylanases - chemistry; Endo-1,4-beta Xylanases - isolation & purification; Enzyme Stability; Fungal Proteins - chemistry; Fungal Proteins - isolation & purification; Hydrolysis; Purification; Xylooligosaccharides; Zea mays - chemistry; β-1, 4-Endoxylanase; AfXynA, β-1; MOPS; SCLC; Corncobs; β-1, 4-Endoxylanase; Aspergillus flavus; Purification; DTT; Xylooligosaccharides; DNS; TLC; DP; Characterization; SDS-PAGE; pNP; CMC; MES; XOs; HPLC
• ISSN: 1046-5928; 1096-0279
• DOI: 10.1016/j.pep.2018.10.006

A new extracellular xylanase was purified from a non-toxic mesophilic fungus Aspergillus flavus, and characterized as the β-1, 4-endoxylanase (designated as AfXynA) that appeared in a single protein band on SDS-PAGE with a molecular mass of 20.2 kDa, which is different from all other reported xylanases from the same strain. The AfXynA exhibited a specific activity of 838.2 U/mg. Its optimal temperature and pH were determined to be 55 °C and 7.5, respectively. It was stable up to 50 °C and within pH 3.5–10.5. AfXynA also exhibited an excellent tolerance to various proteases. This new xylanase had an endohydrolytic mode of action and could hydrolyze xylotriose to xylobiose through transglycosylation. It could efficiently degrade xylan to mainly yield xylobiose, xylotriose, xylopentose and xylohexaose. In addition, the AfXynA was effective in hydrolyzing pretreated corncobs, and shows a great potential in the production of xylooligosaccharides. These unique enzymatic properties make the AfXynA attractive for more biotechnological applications. [Display omitted] •A new found xylanase (designed AfXynA) from Aspergillus flavus was first reported.•AfXynA's molecular mass was new compared with all reported xylanases from A. flavus.•AfXynA displayed an excellent stability under a broad pH range from 3.5 to 10.5•AfXynA exhibited strong tolerance to various cations and proteases.•AfXynA effectively xylanolytic hydrolysis of agro-wastes for the production of XOs.