Dye and Colorant Bleaching

Dyes and colorants are diverse molecules with many unsaturated bonds and/or chromogenic groups whose interaction give rise to different colors. They are often prone to laccase oxidation, which in some cases lead to decolorization. Thus lac-cases have potential for dyeing, waste treatment, and paper recycling applications [1, 2, 5, 6, 8, 9, 48, 56, 56a].

Research on the ability of laccases to oxidize acid, anthraquinoid, azo, indigoid, heterocyclic, phthalocyanine, stilbene, triarylmethane, and other types of dye continues [42, 57-62]. Using mediators may extend laccase oxidation to more recalcitrant dyes, with efficacy depending on the reactivity and stability of selected mediators [58, 63-65]. Immobilizing a laccase may enhance its stability, resistance to inhibitors, or recyclability [42, 61]. In addition to being decolorized or degraded, dyes may be polymerized or attached to other substances (for example, humic acid), allowing easy physical removal.

Degrading the dyes in dyehouse effluent by laccase oxidation could significantly reduce environment pollution, enhance water reuse, or prevent undesirable cross-dyeing. Bleaching the dyes in recycled papers by laccase could reduce the overall cost. Applying laccase to the finishing of dyed denim has been commercialized, in which the enzyme is used to bleach the indigo dye to achieve a desirable appearance of the final product (see Section 2.2.2.2).

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Qigong also spelled Ch'i Kung is a potent system of healing and energy medicine from China. It's the art and science of utilizing breathing methods, gentle movement, and meditation to clean, fortify, and circulate the life energy qi.

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