Abstract: An ionic liquid, i.e., 1-ethyl-3-methylimidazolium ([EMIM] OAc), was used to treat two natural plant fiber (Salix psammophila and cotton). The effects of this pretreatment on the enzymatic degradation of these two materials were investigated in present study. The optimum condition for degradation was obtained as 3.64 mL pH 5 citric acid-sodium citrate buffer solution was added to 5g 4% natural plant fiber[EMIM] OAc solution. A reaction system with 55 g/L fiber substrate was obtained. The optimal ratio of enzyme to substrate was 0.5:1(mL:g), and the optimal reaction temperature and reaction time were 55℃ and 25 h, respectively. Under the optimal condition, the enzymatic degradation of the two natural plant fiber was beyond 90%. The FT-IR showed that the hydrogen bondings of fiber were broken by [EMIM] OAc in the process of dissolution. It resulted in a fiber material with more amorphous pattern. These changes would increase the accessibility between fiber and cellulase. This led to more enzymatic degradation of cellulose.

Key words: ionic liquid, natural plant fiber, enzymatic degradation