Efficient extraction, compositional determination of tobacco stem via optimized hydrothermal treatment for efficient cellulose bioconversion

Hydrothermal pretreatment (HTP) has long been considered as an efficient and green treatment process to separate the components of lignocellulosic biomass. However, the theoretical investigation of HTP on the agricultural wastes and non-woody biomass has been rarely reported. Herein, one of the worldwide important industrial and agricultural wastes, tobacco stem (TS) was hydrothermally treated under various temperatures. A series of morphological observations on cell wall structures, and chemical compositional analyses were performed to investigate the deconstruction effects of HTP on TS. Especially, the degradation behavior of xylan, the major component of hemicellulose polysaccharides, was carefully determined, achieving the maximum removal rate of ~ 72%. Increased pretreatment temperature may result in higher ratio of xylose (~ 11%), xylan with low degree of polymerization (DP), and content of xylooligosaccharides in hydrolysates reached the maximum of ~ 51%. Besides, TS treated by HTP at 110 ℃ exhibited the highest cellulase hydrolysis yield of 77.4%, due to the xylan degradation and lower relative lignin ratio. Therefore, the present work may provide comprehensive understandings on the utilization and bioconversion of TS as well as other lignocellulosic agricultural wastes.