XYLANASE PRODUCTION IN ASPERGILLUS-NIDULANS - INDUCTION AND CARBON CATABOLITE REPRESSION

The induction of the synthesis of extracellular xylanases was investig ated in the fungus Aspergillus nidulans using a number of compounds, i ncluding xylans of different origin, monosaccharides, xylooligosacchar ides and xylose derivatives. Certain xylans (wheat arabinoxylan, oat s pelt xylan, birchwood xylan and 4-O-methyl-D-glucurono-D-xylan) were f ound to be the most powerful inducers. Also, xylooligosaccharides such as xylobiose, xylotriose and xylotetraose served as inducers, their e fficiency being directly related to their chain length. Xylose, on the contrary, was not a true inducer. Of the three endo-beta-(1,4)-xylana ses secreted by A. nidulans, that of 24 kDa was not under carbon catab olite repression, whereas the other two, of 22 and 34 kDa, were under glucose repression mediated by the creA gene product.