Enhanced hydrogen production and biological saccharification from spent mushroom compost by Clostridium thermocellum 27405 supplemented with recombinant β-glucosidases

Clostridium thermocellum 27405 is a potential consolidated bioprocessing (CBP) strain due to the efficient lignocellulose degradation ability. Here, the spent mushroom substrate (SMS), a lignocellulosic byproduct of agriculture, was used as a substrate for hydrogen production by C. thermocellum . SMS showed a good performance for hydrogen production and the hydrogen production was significantly enhanced by C. thermocellum supplemented with β-glucosidases, with the highest production reaching 56.0 mM, an increase of 37%. Additionally, β-glucosidase and Triton X-100 had a synergistic effect on biological saccharification , resulted in an accumulation of 5.06 g/L reducing sugars, an increase of 28%. However, fusion β-glucosidase showed no improvement on hydrogen production and biological saccharification. The present study demonstrates the different influences of β-glucosidase and fusion β-glucosidase on hydrogen production and biological saccharification in CBP system and provides valuable information on the biodegradation of SMS using C. thermocellum .