Effects of Xylanase Pretreatment on the Quality of Refiner Mechanical Mulberry Branch Fibers

We performed xylanase pretreatment prior to mechanical refining in the production of mulberry branch fibers, with the objective of saving energy and studying the effects of such pretreatment on the quality of the fibers. To determine the effects of the enzyme action, we analyzed the energy required for refining, related yield, and the dimension, deformation, and morphology of the fibers. We found that, with the xylanase pretreatment, the refining energy was reduced by 4%, with the yield of fibers being maintained at >85%. In addition, the fiber bundles were defibered further, resulting in reduced average length of the fiber. Furthermore, the fiber widths increased because of the improved swelling effect of the xylanase pretreatment. However, in some instances, the fine elements were reduced. With a low enzyme dosage, the fiber coarseness decreased remarkably and, because of the swelling and softening effects of the xylanase pretreatment on the mulberry branches, the fiber kink ratios and curl were reduced. Additionally, the mulberry branch tissue was loosened, facilitating fiber separation. In view of these findings, the biomechanical process could be a potentially green and efficient process for the manufacturing of mulberry branch fibers.