<P>Abstract</P><P>The heterologous secretion of xylanase B from <I>Penicillium purpurogenum</I> using glucose as inducer was performed in <I>Aspergillus nidulans</I>. For this purpose, plasmid pEVXB, containing the xylanase B cDNA (including its own signal peptide) under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter, was constructed and used to transform <I>A. nidulans</I>. Analysis of transformed clones showed that several of them secreted extracellular xylanase activity when grown in a medium containing glucose. The clone showing the highest xylanase activity was chosen for further work. When this clone was grown on glucose, xylanase activity (0.72 U/ml), was detected in the culture supernatant. This was confirmed by a zymogram analysis and by the amplification of <I>xynB</I> cDNA from this clone. To our knowledge, this is the first example of the production of a xylanase from <I>Penicillium</I> in heterologous fungal hosts using glucose as inducer.</P>