3. Results and discussion3.1. Deter

3. Results and discussion
3.1. Determination of SEPOCS and lignocellulosic hydrolyzates
composition
The main compositions of the SEPOCS (dry weight basis) were
calculated. The major component was cellulose (56.46%). The acid
insoluble lignin and acid-soluble lignin were 31.24% and 6.86%,
respectively. And hemicellulose accounted for only 2.26%. After
enzymatic hydrolysis, the compositions in the resultant hydrolyzates
were as follows: 87.42 g l1 glucose, 7.51 g l1 cellobiose,
4.74 g l1 xylose, 2.76 g l1 glycerol, 0.83 g l1 xylitol, and
0.13 g l1 acetic acid, respectively. A schematic diagram of the entire
process for preparation of the corn stover hydrolyzates was
showed in Fig. 1.
3.2. Selection of optimal fermentation temperature and initial glucose
concentration
Thermophilic Bacillus sp. NL01 strain was isolated at a relatively
high temperature. To further determine its optical fermentation
temperature, Bacillus sp. NL01 was incubated at 40, 45, 50, and
55 C for L-lactic acid production. The best L-lactic acid concentration,
57.2 g l1, was obtained at 50 C. At other temperatures, the Llactic
acid concentration was no more than 50 g l1. Therefore, all
the following fermentations were conducted at 50 C.
Next, Bacillus sp. NL01 was cultured under different initial glucose
concentrations. Many reports had indicated that sugar osmotic