| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 2.35 MB | Adobe PDF |
Orientador(es)
Resumo(s)
In this work, an environment-friendly enzymatic strategy was developed for the valorisation of dye-containing wastewaters. We set up biocatalytic processes for the conversion of azo dyes representative of the main classes used in the textile industry into valuable aromatic compounds: aromatic amines, phenoxazinones, phenazines, and naphthoquinones. First, purified preparations of PpAzoR azoreductase efficiently reduced mordant, acid, reactive, and direct azo dyes into aromatic amines, and CotA-laccase oxidised these compounds into phenazines, phenoxazinones, and naphthoquinones. Second, whole cells containing the overproduced enzymes were utilised in the two-step enzymatic conversion of the model mordant black 9 dye into sodium 2-amino-3-oxo-3H-phenoxazine-8-sulphonate, allowing to overcome the drawbacks associated with the use of expensive purified enzymes, co-factors, or exquisite reaction conditions. Third, cells immobilised in sodium alginate allowed recycling the biocatalysts and achieving very good to excellent final phenoxazine product yields (up to 80%) in water and with less impurities in the final reaction mixtures. Finally, one-pot systems using recycled immobilised cells co-producing both enzymes resulted in the highest phenoxazinone yields (90%) through the sequential use of static and stirring conditions, controlling the oxygenation of reaction mixtures and the successive activity of azoreductase (anaerobic) and laccase (aerobic).
Descrição
Palavras-chave
Laccases Aromatic amines Whole-cell catalysis Phenazines Phenoxazinones Azoreductase
Contexto Educativo
Citação
FERNANDES, Ana; [et al] – Wasteful azo dyes as a source of biologically active building blocks. Frontiers in Bioengineering and Biotechnology. ISSN 2296-4185. Vol. 9 (2021), pp. 1-9
Editora
FRONTIERS MEDIA SA