Xylanase 및 peroxidase를 이용하여 kraft pulp의 표백효율을 향상시키기 위한 방법을 연구하였다. Xylanase를 이용한 kraft pulp의 표백효율은 pH9 완충용액에서 가장 높았으며, 40-50℃에서 3시간 이상 반응할 경우 충분한 표백효율을 얻을 수 있었다. Kraft pulp의 표백효율은 xylanase만을 사용하였을 경우보다 xylanase와 함께 peroxidase, H₂O₂(0.1 mM) 및 페놀성 물질(1 mM)을 사용할 경우 더욱 증가하였다. 페놀성 물질 중 guaiacol을 사용할 경우 표백효율이 가장 높았다. Scaleup(5 L 액상반응기) 실험에서는 xylanase와 peroxidase의 활성이 교반에 의한 shear force에 의하여 감소하였다. 또한 guaiacol을 radical carrier로서 사용할 경우 pulp용액에 H₂O₂, guaiacol, peroxidase의 순으로 주기적으로 첨가하였을 경우 가장 높은 표백효율을 얻을 수 있었으며, 이때 kraft pulp의 kappa number는 초기의 18.25에서 효소반응 및 NaOH(0.5N)추출 후 9.62로 감소하였다. 또한 효소를 사용함으로서 kraft pulp의 알칼리추출 효율을 크게 향상시킬 수 있었다.

The pretreatments of kraft pulp with an alkaline xylanase and a peroxidase were studied to enhance the bleaching efficiency. Xylanase was most effective in a buffer solution of pH9. The pretreatment of kraft pulp with sylanase for more than 3 hours at 40℃ resulted in a sufficient bleaching effect. The pretreatments of kraft pulp with the simultaneous use of xylanase, peroxidase, H₂O₂(0.1mM), and a phenolic compound(1m M) increased the bleaching efficiency as compared to the pretreatments with xylanase only. Guaiacol was most effective among the phenolic compounds used. Results from scaled-up pretreatments(5L reactor) of kraft pulp showed that xylanase and peroxidase can lose their activities by the shear force caused by the agitation of the pulp solution. Intermittent addition of H₂O₂, guaiacol, and peroxidase, in this turn, resulted in the best bleaching efficiency of kraft pulp. In this case the kappa number of kraft pulp decreased from the initial value of 18.25 to 9.62 after the enzymatic pretreatment followed by an alkaline extraction in a 0.5N NaOH solution. Enzymatic pretreatments of kraft pulp enhanced the alkaline extraction efficiency to a great extent.

Enzyme Bleaching Kraft-Pulp Xylanase Peroxidase

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