Green utilization of sorghum straw by coupled hydrothermal pretreatment and cellulase hydrolysis for bacillomycin D production under fed-batch mode

The present work explored the coupled hydrothermal pretreatment and cellulase hydrolysis (HPCH) for production of bacillomycin D from sorghum straws by Bacillus subtilis NS-174. The results indicated that HPCH treated sorghum straws had weaker absorption, heavier mass loss and higher crystallinity, and displayed loose and destructive fiber structures. Degradation of hemicellulose and lignin contributhed to yielding glucose and 68.94 g/L of glucose was obtained in HPCH treated hydrolysate. High level of glucose in pretreated sorghum straw hydrolysate was helpful for improving bacillomycin D production. When performed by 3rd round (feeding at 144 h) fed-batch fermentation, bacillomycin D production and production rate were obtained to be 2351.07 mg/L and 113.36 mg/L.h in B. subtilis NS-174, respectively.