Abstract: The xyn I cDNA(GenBank, DQ302412) was amplified with RT-PCR methods from the total RNA extracted from Aspergillus usamii E001. Sequence analysis showed that the cDNA is 881 bp in length including 5' and 3' non-encoding regions, a 111 bp signal peptide encoding region,and a 567 bp mature peptide encoding region which encoded the xylanase(Xyn I) of 188 amino acids. The xylanase gene(xyn I) DNA(GenBank, DQ302413) was amplified with signal primer PCR methods from the genomic DNA extracted from E001. The DNA is 1098 bp in length which included the regions of a promoter, a intron and two exons. Comparison of the homologies of the amino acid sequence of the Xyn I with other xylanases from GenBank was carried out. The results showed that the Xyn I is a new xylanase and belongs to G/11 family.

Key words: Aspergillus usamii, xylanase, xylanase gene(xyn I), sequence analysis