RESUMO

A new xylanase (XYL2) was purified from solid-state cultures of Trichoderma harzianum strain C by ultrafiltration and gel filtration. SDS-PAGE of the xylanase showed an apparent homogeneity and molecular weight of 18 kDa. It had the highest activity at pH 5.0 and 45 degrees C and was stable at 50 degrees C and pH 5.0 up to 4 h xylanase. XYL2 had a low Km with insoluble oat spelt xylan as substrate. Compared to the amino acid composition of xylanases from Trichoderma spp, xylanase XYL2 presented a high content of glutamate/glutamine, phenylalanine and cysteine, and a low content of serine. Xylanase XYL2 improved the delignification and selectivity of unbleached hardwood kraft pulp.

Assuntos

Trichoderma/enzimologia , Xilosidases/isolamento & purificação , Aminoácidos/análise , Cromatografia em Gel , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Ultrafiltração , Madeira , Xilano Endo-1,3-beta-Xilosidase , Xilosidases/química , Xilosidases/metabolismo