Enhanced saccharification of cellulose and sugarcane bagasse by Clostridium thermocellum cultures with Triton X-100 and β-glucosidase/Cellic®CTec2 supplementation

Clostridium thermocellum is the most efficient cellulose-degrading bacterium known for producing cellulosome, which was used to directly degrade sugarcane bagasse (SCB) with limited glucose accumulation. However, the glucose production was significantly enhanced with 0.25% Triton X-100 and 30 U g(-1) of beta-glucosidase supplementation. A glucose accumulation of 21.33 +/- 0.35 g L-1 and substrate degradation of 61.91 +/- 0.77% from 60 g L-1 sodium hydroxide-pretreated SCB were reached, with a 609.41% and 75.53% increase over the control (3.01 +/- 0.26 g L-1, 35.27 +/- 2.91%), respectively. More interestingly, a synergism between C. thermocellum cultures and Cellic (R) CTec2 (30 CBU per g, 1.2 FPU per g substrate) in the enzymolysis of Avicel was observed and the glucose concentration and saccharification ratio of Avicel reached 56.90 +/- 1.20 g L-1 and 94.8% at 60 g L-1 Avicel. Moreover, a highest glucose concentration of 83.17 g L-1 was achieved at 100 g L-1 Avicel. The present work provides an effective and promising process for industrial saccharification of cellulose.