COD was digested using a B F Speed Digester

2.5. Fermentability of the recovered hydrolyzates
The recovered hydrolyzates containing glucose was used for ethanol ABT-378 using S. cerevisiae (Angel Yeast Co., Ltd., China). It was performed as the previous report ( He et al., 2013).
2.6. Analytical method
Reducing sugars was determined with DNS method (Qing et al., 2014). Glucose and ethanol was assayed using HPLC (Waters 600, USA) (He et al., 2014). The cell concentrations were measured by OD660nm using a Gold Spectrumlab 53 spectrophotometer (Shanghai Lengguang Technology Co., Ltd, China) (He et al., 2013). Untreated and pretreated CS samples were measured by scanning electron microscopy (SEM), Fourier transformed IR (FTIR) and X-ray diffraction (XRD) (Qing et al., 2014). Yield of reducing sugars or glucose from cellulosic materials were calculated as follows:Yield of reducing sugars%=[Reducing sugars released]×0.9×100%[CS dry weight]Yield of glucose%=[Glucose released]×0.9×100%[CS dry weight]
Crystallinity index (CrI) was calculated as follows:CrI=(I002-Iam)/I002×100CrI=(I002-Iam)I002×100where I002 is the intensity of the peak at near 22.3°, and Iam is the intensity of the peak at near 18.0°.