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 .
Repeated and high-dose carbendazim applications have caused serious soil carbendazim contamination, and eco-friendly and economical approaches have been suggested to promote carbendazim removal in agricultural soil . Spent mushroom substrate (SMS) is a special recycled resource after harvesting mushrooms and can be utilized in contaminated soil amendment. The SMS application into agricultural soil might increase antibiotic resistance gene abundances, and the health risks of SMS application might be reduced with reasonable management to adjust the related electron transport of soil nitrification or denitrification. In this study, the SMS and nitrification inhibitor dicyandiamide were used to remediate agricultural soil contaminated with the carbendazim, and the carbendazim contents, soil microbial biomass, activities and community and human disease genes were determined. Compared to the control treatment, the combined applications of SMS and dicyandiamide significantly decreased soil carbendazim content by 38.14% but significantly enhanced soil β -glucosidase, chitinase, arylsulfatase, urease and electron transfer system activities. The relative abundances of Proteobacteria and Actinobacteria were increased by 11.0% and 8.2% with the SMS application, respectively. The carbendazim residues were negatively correlated with the soil pH, electron transfer system activities and relative abundances of Proteobacteria and Actinobacteria. The relative abundances of human disease genes were also dramatically increased with the SMS application, but compared to the SMS alone, extra dicyandiamide application significantly reduced the relative abundances of human disease genes in soils. The SMS applications into fungicide-contaminated soils could generate double-edged sword effects of facilitating fungicide dissipation but leading to potential health risk increase, while applying the dicyandiamide with SMS might be an effective strategy to decrease the negative effect of health risk.
危险品化学品经营许可证（带存储）