Characterization of Cellulose Fibers According to Cellulase-Active Microbial Pretreatment

This study evaluated the effects of microbial (Bacillus subtilis, Bacillus licheniformis) pretreatment and mechanical (ball mill) treatment on the nanofibrillation of cellulose. The optimal growth conditions were identified a B. subtilis (pH 6-8, 25℃ and 100 rpm) and B. licheniformis (pH 7, 35℃ and 150 rpm), respectively. As a result of evaluating microbial reducing sugar production from carboxymethyl cellulose, B. subtilis case showed similar trends at most experimental conditions (pH, temperature and rpm) except for pH 5. The maximum amount of reducing sugar by B. licheniformis was achieved at the culture conditions with pH 7, 35℃ and 150 rpm. There was no change in the crystalline structure of cellulose by ball mill and microbial treatment, but, XRD peaks intensity decreased. Cellulose nanofibers were observed after 6 hours ball mill treatment of alpha cellulose with/without the microbial pretreatment. When applying microbial pretreatment, the cellulose nanofibers produced by the ball mill had more longer in length than those without the pretreatment.