Aim of present study was to investigate the interaction of coomassie brilliant blue G-250 (CBBG-250) with bovine serum albumin (BSA) by the multispectroscopic methods. Fluorescence-data showed that the complex of BSA-CBBG-250 forming made the intrinsic fluorescence quenching of BSA by CBBG-250 interaction. BSA also could interact with CBBG-250 and the CBBG-BSA complexes formed in a molar ratio of 1:1. UV-Vis results displayed that the apparent binding (association) constant K a of CBBG-250 with BSA was 5.03 × 10 4 (298 K), 3.04 × 10 4 (303 K), 2.84 × 10 4 (308 K) and 1.99 × 10 4 (313 K) L mol −1 at different temperatures, respectively. The enthalpy change (△H) and entropy change (△S) were respectively calculated to be − 45.32 kJ mol −1 and − 139.18 J mol −1 K −1 , indicating that the hydrogen bonds and Van der Waals forces played dominant roles in the interaction. The results showed that the diphenylamine structure and amino acid residues in the Coomassie Brilliant Blue G-250 had a strong Van der Waals force. The phenyl sulphonic acid group undergoes electrostatic interactions and hydrogen bond interactions with basic amino acids; the compound Coomassie Brilliant Blue G-250 can form a stable complex with BSA.

Switchgrass ( Panicum virgatum , L., Poaceae) with the advantages of high cellulose yield, and high growth even under low input and poor soil quality, has been identified as a promising candidate for production of low-cost biofuels, papermaking, and nanocellulose. In this study, 12 chemical pretreatments on a laboratory scale were compared for different utilization purposes of switchgrass. It was found that the pretreated switchgrass with sodium hydroxide showed considerable potential for providing mixed sugars for fermentation with 11.10% of residual lignin, 53.85% of residual cellulose, and 22.06% of residual hemicellulose. The pretreatment with 2.00% (v/v) nitric acid was the best method to remove 78.37% of hemicellulose and 39.82% of lignin under a low temperature (125 °C, 30 min), which can be used in the production of nanocellulose. Besides, a completely randomized design analysis of switchgrass pretreatments provided the alternative ethanol organosolv delignification of switchgrass for the papermaking industry with a high residual cellulose of 58.56%. Finally, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) were carried out to confirm the changes in functional groups, crystallinity, and thermal behavior of the three materials, respectively, from the optimal pretreatments.