<p>Three endo-(l,4)-β-D-xylanases; (Endo I, Endo II, and Endo III), a (1,4)-β-xylosidase and an (1,4)-β-D-arabinoxylan arabinofuranohydrolase (AXH) were purified from a culture filtrate produced by <em>Aspergillus awamori</em> CMI 142717. In addition to these enzymes, an acetyl xylan esterase (AE) was purified from a culture filtrate produced by <em>Aspergillus niger</em> DS 16813.<p>The enzymes were characterized by determining specific activities, molecular weight, isoelectric point, kinetic parameters (K <sub><font size="-2">m</font></sub> ,V <sub><font size="-2">max</font></sub> ), optimum pH and optimum temperature.<p>Arabinoxylan oligosaccharides were derived from alkali-extracted wheat arabinoxylans by complete digestion with Endo I and III. The structures of unknown oligosaccharides were elucidated by <sup><font size="-2">1</font></SUP>H-n.m.r. spectroscopy. From these structures a model was proposed for the mode of action of Endo I and Endo III towards arabinoxylans. The same oligosaccharides were also used to specify the action of (1,4)-β-xylosidase, AXH and two α-L-arabinofuranosidases towards these arabinofuranosylated arabinoxylan oligosaccharides.<p>The interaction between the purified enzymes was studied by degradation of xylans from rice bran, oat spelt, wheat-flour, larchwood, and birchwood by single and combined actions of these enzymes on these substrates. The cooperativity was monitored by the amount of reducing sugars and by the types of products released.
|Qualification||Doctor of Philosophy|
|Award date||9 Dec 1992|
|Place of Publication||S.l.|
|Publication status||Published - 1992|