TABLE 6.
Specific hydrolysis rates for cellulosic substrates of high crystallinity in cell-free systems
| Organism | Cellulase preparation | Substrate and assay | Sp act (μmol/min/mg) | Reference | |
|---|---|---|---|---|---|
| Isolated component | |||||
| Clostridium cellulolyticum | CelA, expressed in E. coli and chromatographically purified | Avicel; 37°C, RS | 0.11 | 187 | |
| CelC, same | Avicel; 37°C | 0.017 | 186 | ||
| CelE, same | Avicel; 37°C | 0.06 | 206 | ||
| CelF, same | Avicel; 45°C | 0.17 | 564 | ||
| Clostridium thermocellum | Ion exchange-purified celA expressed in E. coli | Avicel; 60°C, RSa, 1 h | 0.083 | 607 | |
| Avicel (summarizes data for 8 components from various studies) | 0.0052-0.083 | 5 | |||
| Neocallimastix patriciarum | Immunoaffinity-purified CELA expressed in E. coli | Avicel; 40°C, RS, 30-60 min | 9.7 | 146 | |
| Crude recombinant CELA | Avicel; 40°C, RS, 30-60 min | 1.7 | 146 | ||
| Crude recombinant CELD | Avicel; 39°C | 0.18 | 767 | ||
| Ruminococcus flavefaciens | Chromatographically purified | Avicel; 39°C, RS | 0.049 | 249 | |
| Trichoderma reesei | Purified CBHI and CBHII | Avicel; 50°C, RS, 3 h | 0.014-0.027 | 682 | |
| Purified CBHI and CBHII | Avicel; 40°C, RS | 0.26-0.48 | 174 | ||
| Chromatographically purified, 5 components tested | Avicel; 30°C, RS, 20 h | 0.002-0.019 | 333 | ||
| Multicomponent mixtures and complexes | |||||
| Clostridum cellulolyticum | Partially purified cellulosome | Avicel | 0.2 | 199 | |
| Clostridium papyrosolvens | Size exclusion chromatography | Avicel | 0.037 | 539 | |
| Clostridium strain A11 | Affinity chromatography | Avicel; 34°C, RS (7) | 0.068 | 45 | |
| Clostridium thermocellum | Crude protein | Avicel, 60°C, 21 h | 0.0066 | 316 | |
| Size exclusion, affinity chromatography (2.1%) | Avicel | 0.1 | 350 | ||
| None (crude extracellular protein) | Avicel | 0.013 | 350 | ||
| Affinity digestion | Avicel; 60°C, RS | 13.2 | 465 | ||
| Affinity chromatography | Avicel; 60°C, RS | 6.0 | 465 | ||
| None (crude extracellular protein) | Avicel, 60°C, RS | 2.9 | 465 | ||
| Affinity digestion | Avicel; 60°C, RS 1 h | 2.4 | —b | ||
| Neocallimastix patriciarum | Crude protein | Avicel; 40°C, RS | 0.27 | 160 | |
| Piromyces strain E2 | Crude extracellular protein | Avicel; 40°C, RS | 0.26 | 160 | |
| Trichoderma reesei | Crude protein | Avicel; 37°C, 21 h | 0.000241 | 316 | |
| None (Celluclast, as received) | Avicel; 50°C, “initial rate” | 0.83 | 490 | ||
| None (crude broth) | Filter paper; 50°C, RS, 1 h | 0.6-0.8 | 177 | ||
| None (Celluclast, as received) | Petreated birch; 45°C, RS, 24 h | 1.0 | 773 | ||
| Chromatofocusing, reconstituted mixtures | Pretreated birch; 45°C, RS, 24 h | 0.34-1.16 | 773 |
a
RS, reducing sugars.
b
Y. Zhang and L. R. Lynd, submitted.