여러 가지 난분해성 색소에 대하여 탈색능을 나타내는 Klebsiella pneumoniae WL-5이 염색폐수처리장의 활성슬러지로부터 분리되었다. 이 세균은 정치배양과 at pH 6-8 및 $30-35^{circ}C$에서 높은 탈색능을 나타내었다. Congo Red색소에 대해서는 $200;{mu}M$ 농도에서 12시간 배양하였을 때 90% 이상이 탈색되었고, Malachite Green, Brilliant Green, Reactive Black-5에 대해서는 $10;{mu}M$ 농도에서 80% 이상이 탈색되었지만, Reactive Red-120, Reactive Orange-16, Crystal Violet에 대해서는 $10;{mu}M$ 농도에서 각각 46%, 25%, 13%의 비교적 낮은 탈색능을 나타내었다. 트리페닐메탄계 색소는 세포표면에의 흡착에 의한 탈색을 나타내었고, 아조계 색소는 지금까지 알려져 있지 않는 새로운 효소반응계에 의해서 탈색된다는 것을 제시하였다.
A Klebsiella pneumoniae WL-5 with the capability of decolorizing several recalcitrant dyes was isolated from activated sludge of an effluent treatment plant of a textile and dyeing industry. This strain showed a higher dye decolorization under static condition and color removal was optimal at pH 6-8 and $30-35^{circ}C$. More than 90% of its color of Congo Red were reduced within 12 hr at $200;{mu}M$ dye concentration. Malachite Green, Brilliant Green and Reactive Black-5 lost over 85% of their colors at $10;{mu}M$ dye concentration, but the percentage decolorization of Reactive Red-120, Reactive Orange-16, and Crystal Violet were about 46%, 25%, and 13%, respectively. Decolorizations of Congo Red and triphenylmethane dyes, such as Malachite Green, Brilliant Green, and Crystal Violet were mainly due to adsorption to cells, whereas azo dyes, such as Reactive Black-5, Reactive Red-120, and Reactive Orange-16 seemed to be removed by biodegradation through unknown enzymatic processes.
