TABLE 6.

Specific hydrolysis rates for cellulosic substrates of high crystallinity in cell-free systems

OrganismCellulase preparationSubstrate and assaySp act (μmol/min/mg)Reference
Isolated component
    Clostridium cellulolyticumCelA, expressed in E. coli and chromatographically purifiedAvicel; 37°C, RS0.11187
CelC, sameAvicel; 37°C0.017186
CelE, sameAvicel; 37°C0.06206
CelF, sameAvicel; 45°C0.17564
    Clostridium thermocellumIon exchange-purified celA expressed in E. coliAvicel; 60°C, RSa, 1 h0.083607
Avicel (summarizes data for 8 components from various studies)0.0052-0.0835
    Neocallimastix patriciarumImmunoaffinity-purified CELA expressed in E. coliAvicel; 40°C, RS, 30-60 min9.7146
Crude recombinant CELAAvicel; 40°C, RS, 30-60 min1.7146
Crude recombinant CELDAvicel; 39°C0.18767
    Ruminococcus flavefaciensChromatographically purifiedAvicel; 39°C, RS0.049249
    Trichoderma reeseiPurified CBHI and CBHIIAvicel; 50°C, RS, 3 h0.014-0.027682
Purified CBHI and CBHIIAvicel; 40°C, RS0.26-0.48174
Chromatographically purified, 5 components testedAvicel; 30°C, RS, 20 h0.002-0.019333
Multicomponent mixtures and complexes
    Clostridum cellulolyticumPartially purified cellulosomeAvicel0.2199
    Clostridium papyrosolvensSize exclusion chromatographyAvicel0.037539
    Clostridium strain A11Affinity chromatographyAvicel; 34°C, RS (7)0.06845
    Clostridium thermocellumCrude proteinAvicel, 60°C, 21 h0.0066316
Size exclusion, affinity chromatography (2.1%)Avicel0.1350
None (crude extracellular protein)Avicel0.013350
Affinity digestionAvicel; 60°C, RS13.2465
Affinity chromatographyAvicel; 60°C, RS6.0465
None (crude extracellular protein)Avicel, 60°C, RS2.9465
Affinity digestionAvicel; 60°C, RS 1 h2.4b
    Neocallimastix patriciarumCrude proteinAvicel; 40°C, RS0.27160
    Piromyces strain E2Crude extracellular proteinAvicel; 40°C, RS0.26160
    Trichoderma reeseiCrude proteinAvicel; 37°C, 21 h0.000241316
None (Celluclast, as received)Avicel; 50°C, “initial rate”0.83490
None (crude broth)Filter paper; 50°C, RS, 1 h0.6-0.8177
None (Celluclast, as received)Petreated birch; 45°C, RS, 24 h1.0773
Chromatofocusing, reconstituted mixturesPretreated birch; 45°C, RS, 24 h0.34-1.16773
  • a RS, reducing sugars.

  • b Y. Zhang and L. R. Lynd, submitted.