Fig. 7

Hydrolysis of various carbohydrate substrates by cellulosome fractions of B. cellulosolvens. Two fractions (I: high-molecular-weight, and II: lower molecular-weight, separated by gel filtration chromatography as described in the “Methods” section), containing cellulosomal complexes derived from cells grown on either cellobiose (CB) or microcrystalline cellulose (MCC), were examined for catalytic activity on a CMC (carboxymethyl cellulose), b MCC (Avicel), c PASC (phosphoric acid-swollen cellulose), d beechwood xylan, and e wheat straw, in order to demonstrate their degradation abilities. The cellulosomal fractions were tested (at 40 °C, optimal activity temperature) separately or combined (combination of peak I and II from the same growth medium), in order to examine possible synergistic effects. In order to avoid possible inhibition by degradation products, recombinant β-glucosidase from Thermobifida fusca (BglC) was added to the catalytic reactions of the combined fractions of B. cellulosolvens and to the C. thermocellum cellulosome. BglC was chosen due to its optimal temperature (50 °C), and it was active both at 40 °C for B. cellulosolvens activity and at 60 °C for C. thermocellum (Ct) activity. The C. thermocellum cellulosome (cells grown on MCC as substrate) was tested as a positive control for catalytic activity of the B. cellulosolvens cellulosomes