NOVELTY - A modified cellulase enzyme (E1) comprising a modified linker peptide positioned between a cellulase catalytic domain and a carbohydrate binding module, is new. The modified linker peptide is 6-60 amino acids in length and of which at least 50% the amino acids are proline, serine or threonine; the modified linker peptide comprises at least one amino acid substitution, insertion, or deletion that results in a decrease in calculated isoelectric point of the linker peptide, and/or an increase in ratio of threonine:serine in the linker peptide, relative to a parental linker peptide.    USE - For hydrolysis of cellulose or pretreated lignocellulose to produce fermentable sugars, sugar alcohols or fuel alcohol (claimed), for industrial processing of lignocellulose for the production of sugars and other products.    ADVANTAGE - The modified linker peptide in the modified cellulase enzyme confers an improved cellulose hydrolyzing activity in the presence of lignin and/or a reduction in lignin binding, relative to a parental cellulase comprising the parental linker.    DETAILED DESCRIPTION - A modified cellulase enzyme (E1) comprising a modified linker peptide positioned between a cellulase catalytic domain and a carbohydrate binding module, is new. The modified linker peptide is 6-60 amino acids in length and of which at least 50% the amino acids are proline, serine or threonine; the modified linker peptide comprises at least one amino acid substitution, insertion, or deletion that results in a decrease in calculated isoelectric point of the linker peptide; and/or an increase in ratio of threonine:serine in the linker peptide, relative to a parental linker peptide from which the modified linker peptide is derived; the modified linker peptide confers to the modified cellulase an increase in cellulose hydrolyzing activity in the presence of lignin and/or a reduction in lignin binding, relative to a parental cellulase comprising the parental linker. INDEPENDENT CLAIMS are included for the following:    (1) an isolated genetic construct (G1) comprising nucleic acid sequence encoding the modified cellulase enzyme (E1);    (2) an isolated genetically modified microbe comprising the genetic construct (G1);    (3) preparation of the modified cellulase enzyme (E1);    (4) hydrolyzing a cellulose substrate involving contacting the substrate with the modified cellulase enzyme (E1) in the presence of lignin; and    (5) production of fermentable sugars, sugar alcohols or fuel alcohol involving contacting a pretreated lignocellulosic substrate with the modified cellulase enzyme (E1).