Enzyme–microbe synergy during cellulose hydrolysis by Clostridium thermocellum

Lu et al. 10.1073/pnas.0605381103.

Supporting Information

Files in this Data Supplement:

Fig. 4. pH and concentrations of fermentation products in batch culture of C. thermocellum on Avicel. Data are for the experiment depicted in Fig. 1A.

Fig. 5. pH and concentrations of fermentation products in batch SSF of Avicel by T. thermosaccharolyticum in the presence of added C. thermocellum cellulosome. Data are for the experiment depicted in Fig. 1B.

Fig. 6. Cellulose hydrolysis and sugar accumulation for cell-free enzyme control 1. Data are for the experiment depicted in Fig. 2.

Fig. 7. Continuous simultaneous saccharification and fermentation of Avicel by T. thermosaccharolyticum in the presence of 0.064 g per liter of purified C. thermocellum cellulosome. Feed cellulose concentration = 4.65 g er liter, t = 19.2 h. Data from this experiment are presented as "SSF steady state 2" in Table 1. The experiment was switched from continuous to batch at 180 h to prevent further accumulation of cellobiose; continuous feeding was reinitiated at 195 h.

Fig. 8. Schematic arrangement of the experimental apparatus for continuous SSF.

Table 2. Cellulase and specific activity for batch and continuous experiments

Conditions correspond to those reported in Table 1, with cell-free control 1 as described in the text. Activity measurements are carried out in the presence of metabolically inactive cells as described in Materials and Methods. Numbers in parentheses are standard deviations for replicate cultures (batch) and for successive steady-state samples (continuous).

Table 3. Standard deviations and carbon recoveries for batch and continuous experiments

Conditions correspond to those reported in Table 1. Numbers in parentheses are standard deviations for replicate cultures (batch) and for successive steady-state samples (continuous). For continuous culture experiments, the cellulose concentrations listed in Table 3 are for samples taken from steady-state fermentors. Carbon recovery is calculated using Eq. 1 from Supporting Text (for microbial conversion) or Eq. 2 from Supporting Text (for SSF), with initial cellulose concentrations for continuous culture experiments taken from Table 1

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