On the modes of action of three xylanases produced by a strain of aspergillus niger van tieghem.

The modes of action of three xylanases (I, II and III) produced by Aspergillus niger van Tieghem on several substrates were investigated. Xylanase I possesed the strongest activity against xylooligosaccharides among the three enzymes and converted them into xylose and xylobiose. Xylanase II and III catalyzed a glycosylating reaction and produced higher polymerized xylooligosaccharides from xylotetraose or xylopentaose. Among three enzymes, xylanase II could split α1, 3-arabinofuranosidic bond of arabinose-xylose mixed oligosaccharides. In the case of hydrolysis by three xylanases on xylan and arabinoxylan, the maximum hydrolysis degree and the reaction products were compared with each other. From the results, some speculation were made concerning the modes of action of the enzymes.