CLONING, SEQUENCING AND ENHANCED EXPRESSION OF THE TRICHODERMA-REESEIENDOXYLANASE-II (PI 9) GENE XLN2

The Trichoderma reesei xln2 gene coding for the pI9.0 endoxylanase was isolated from the wild-type strain QM6a. The gene contains one intron of 108 nucleotides and codes for a protein of 223 amino acids in whic h two putative N-glycosylation target sites were found. Three:e differ ent T. reesei strains were transformed by targeting a construct compos ed of the xln2 gene, including its promoter, to the endogenous cbh1 lo cus. Highest overall production levels of xylanase were obtained using T. reesei ALK02721, a genetically engineered strain, as a host. Integ ration into the cbh1 locus was not required for enhanced expression un der control of the xln2 promoter.