The cellobiohydrolase-encoding gene from the anaerobic chytrid Neocallimastix patriciarum (Npcel6A) was heterologously produced in Saccharomyces cerevisiae. Recombinant cellulase activity was detected on soluble cellulose substrates however little activity was found on Avicel. The unusual Asn-rich linker region along with the carbohydrate-binding module (CBM) of NpCel6A was replaced with a Ser/Thr/Pro-rich linker and CBM from the TrCel6A of Trichoderma reesei. The yeast producing the hybrid cellulase had significantly lower activity on filter paper than the original NpCel6A. When the Asn-rich linker was fused to the catalytic domain of TrCel6A, significantly higher cellulase activity was found on filter paper than the original TrCel6A. (C) 2009 Elsevier Inc. All rights reserved.