Abstract: The present invention relates to a modified Family 5 cellulase comprising a substitution of an amino acid at position 363 with a non-native alanine, serine or threonine, the position determined from alignment of the modified Family 5 cellulase with amino acids 71-397 of a Trichoderma reesei Cel5A amino acid sequence as set forth in SEQ ID NO:1 and enzyme mixtures comprising same. Additionally provided is a genetic construct comprising a nucleic acid sequence encoding the modified Family 5 cellulase and a genetically modified microbe comprising the genetic construct. The invention also provides a process for producing the modified Family 5 cellulase.