TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preparation (claimed): preparation of the modified cellulase enzyme (E1) involves:(1) transforming a host microbe with the genetic construct (G1) to produce recombinant strains;(2) selecting recombinant strains expressing the modified cellulase enzyme; and(3) culturing selected recombinant strains in submerged liquid fermentations under conditions that induce expression of the modified cellulase enzyme.Preferred Components: The modified linker peptide comprises 20-50 amino acids, and confers at least a 10% increase in cellulose hydrolyzing activity in the presence of lignin, and/or at least 1.2-fold reduction in lignin binding, relative to the parental cellulase. The amino acid substitutions, insertions, or deletions result in at least a 0.2 unit decrease in calculated isoelectric point of the linker peptide, and/or at least about a 10% increase in ratio of threonine:serine in the linker peptide. The cellulase catalytic domain is a member of glycosyl hydrolase family 5, 6, 7, 9, 12, 45, or 61. The modified linker peptide, cellulase catalytic domain and carbohydrate binding domain are from a fungal cellulase. The fungal cellulase is from: Trichoderma ssp., Aspergillus ssp., Hypocrea ssp., Humicola ssp., Neurospora ssp., Orpinomyces ssp., Gibberella ssp., Emericella ssp., Chaetomium ssp., Chrysosporium ssp., Myceliophthora ssp., Fusarium ssp., Penicillium ssp., Magnaporthe ssp., Phanerochaete ssp., Trametes ssp., Lentinula edodes, Gleophyllum trabeiu, Ophiostoma piliferum, Corpinus cinereus, Geomyces pannorum, Cryptococcus laurentii, Aureobasidium pullulans, Amorphotheca resinae, Leucosporidium scotti, Cunninghamella elegans, Thermomyces lanuginosa, or Sporotrichum thermophile. The fungal cellulase is cellobiohydrolase from Trichoderma reesei and is selected from Cel7A, Cel6A, Cel7B, Cel5A, Cel45A, or Cel61A. The modified cellulase (E1) further comprises at least one additional functional domain selected from a glycosyl hydrolase domain, a carbohydrate binding module, a cohesin domain, a dockerin domain and a fibronectin-like domain. The decrease in the calculated isoelectric point of the modified linker peptide is achieved by: (a) replacement of at least one neutral or basic amino acid by acidic amino acids, (b) replacement of at least one basic amino acid by neutral amino acids, (c) insertion of at least one acidic amino acid, and/or (d) deletion of at least one basic amino acid; and the increase in threonine:serine ratio is achieved by: (a) replacement of at least one non-threonine amino acid by threonine, (b) replacement of at least one serine by threonine, (c) insertion of at least one threonine, (d) deletion of at least one serine, and/or (e) replacement of at least one serine by a non-threonine amino acid. The isolated genetically modified microbe is a species of yeast or filamentous fungus. The yeast is a species of Saccharomyces, Pichia or Hansenula and the filamentous fungus is a species of Trichoderma, Hypocrea, Aspergillus, Fusarium, Humicola, Chrysosporium, Myceliopthora or Neurospora. The modified linker peptide is selected from 15 amino acid sequences as given in the specification, e.g. a peptide sequence comprising 44 amino acids as given in the specification (linkTrCel6A-G40D) (SEQ ID NO:26); a peptide sequence comprising 44 amino acids as given in the specification (linkTrCel6A-G72D) (SEQ ID NO:29); a peptide sequence comprising 44 amino acids as given in the specification (linkTrCel6A-V81D) (SEQ ID NO:31); a peptide sequence comprising 44 amino acids as given in the specification (linkTrCel6A S-T) (SEQ ID NO:37); a peptide sequence comprising 24 amino acids as given in the specification (linkTrCel7A R-E) (SEQ ID NO:40); and a peptide sequence comprising 24 amino acids as given in the specification (linkTrCel7A R-E/S-T) (SEQ ID NO:41). The cellulase catalytic domain exhibits at least 60% amino acid sequence identity to amino acids 83-447 of cellobiohydrolase from Trichoderma reesei (Cel6A) (SEQ ID NO:1) (SEQ ID NO:not defined) or to amino acids 1-437 of Trichoderma reesei Cel7A (SEQ ID NO:3) (SEQ ID NO:not defined). The amino acids 83-447 of Trichoderma reesei Cel6A comprise at least one amino acid substitution selected from: Tyr103His, Tyr103Lys, Tyr103Arg, Tyr103Ala, Tyr103Val, Tyr103Leu, Tyr103Pro, Lys129Glu, Met134Ile, Met134Gln, Met134Thr, Met134Val, Met134Tyr, Leu136Val, Leu136Ile, Ser186Lys, Ser186Thr, Ser186Tyr, Gln204Lys, Gly213Asp, Ala322Asp, Gln363Glu, Gly365Asp, Gly365Glu, Gly365Gln, Gly365Ser, Arg410Ala, Arg410Phe, Arg410Leu, Arg410Gln, Arg410Ser and Ser413Pro. The carbohydrate binding module exhibits at least 50% amino acid sequence identity to at least one carbohydrate binding module selected from: 8 amino acid sequences comprising 36 amino acids as given in the specification (SEQ ID NOs:48 to 55). EXAMPLE - No suitable example is given.