Xylanase production in<i>Aspergillus nidulans</i>: induction and carbon catabolite repression

Abstract

The induction of the synthesis of extracellular xylanases was investigated in the fungus &lt;it&gt;Aspergillus nidulans&lt;/it&gt; using a number of compounds, including xylans of different origin, monosaccharides, xylooligosaccharides and xylose derivatives. Certain xylans (wheat arabinoxylan, oat spelt xylan, birchwood xylan and 4-O-methyl-D-glucurono-D-xylan) were found to be the most powerful inducers. Also, xylooligosaccharides such as xylobiose, xylotriose and xylotetraose served as inducers, their efficiency being directly related to their chain length. Xylose, on the contrary, was not a true inducer. Of the three endo-β-(1,4)-xylanases secreted by &lt;it&gt;A. nidulans&lt;/it&gt;, that of 24 kDa was not under carbon catabolite repression, whereas the other two, of 22 and 34 kDa, were under glucose repression mediated by the &lt;it&gt;creA&lt;/it&gt; gene product.