Abstract The gene structure of the T.reesei cellobiohydrolase Ⅱ(cbh2) was reconstructed by fusing with additional genes which encode catalytic domains from EGⅣ(cdE ) and CBHⅡ(cdC ), respectively. The target genes were obtained through PCR and the gene cdE was ligated on the 5’ end of cbh2 while cdC was ligated on the 3’ end through gene fusion, generating reconstructed genes cdE –cbh2 and cbh2-cdC, respectively. The reconstructed genes were expressed in Pichia GS115 and results the recombinant strains P.pastoris PEC11 and P.pastoris PCC16 with the most efficient activities. When cultivated in the optimized incubation condition, the CMC activities of the cultivation supernatant of P.pastoris PEC11 and P.pastoris PCC16 attained 3.87U/ml and 7.66U/ml, respectively. The modified CBHⅡwith an additional catalytic domain from itself improved the CMC activity about 2-fold.
