Purification and characterization of endoxylanase Xln-2 from Aspergillus niger B03

Authors : Georgi DOBREV, Boriana ZHEKOVA

Pages : 7-13

View : 17 | Download : 7

Publication Date : 2012-12-01

Article Type : Research Paper

Abstract :An extracellular multiple form of endoxylanase was isolated from the xylanolytic complex of Aspergillus niger B03. The enzyme was purified to a homogenous form using ultrafiltration, anion exchange chromatography, and gel filtration. It was a nonglycosylated protein with a molecular weight of 20,000 Da as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 21,000 Da as determined by gel filtration. The optimal pH for the enzyme action was 5.0 and the optimal temperature was 55 °C. Endoxylanase stability was significantly improved in the presence of glycerol and sorbitol. The enzyme activity was activated by Mn2+ and Co2+, and it was inhibited by Ag+, Cu2+, Fe3+, Fe2+, and Pb2+. The substrate specificity and the product profile of the enzyme suggested that it was an endoxylanase. The enzyme showed a synergism with another endoxylanase from Aspergillus niger B03 in xylan hydrolysis.
Keywords : Key words Endoxylanase, purification, characterization, Aspergillus niger, xylan