Effect of refining on delignification with a laccase /xylanase treatment

Abstract

Previous research has demonstrated that a laccase/xylanase system (LXS) from white-rot fungus (Lentinus lepideus) has the same ability to delignify as a laccase/mediator system (LMS). In order to enhance delignification ability of LXS treatment, the effect of refining on delignification with LXS treatment of Masson pine (Pinus massoniana) pulp was investigated by refining the pulp in a PFI mill to different revolutions (14,000/21,000/35,000/42,000/56,000) prior to LXS treatment (enzyme dosage 5/10/15IU/g o.d. pulp). The results indicated that both kappa number and yield of the LXS treated pulp decreased with increasing refining. A substantial delignification without severe yield loss could be achieved by moderate refining prior to LXS treatment. The SEM images suggested that refining increased the accessibility of the material to enzymes and thereby enhanced the delignification ability of LXS. The small cellulase activity detected in the LXS had little effect on the viscosity of the treated pulp even at high enzyme dosage.