Degradação de corantes têxteis reativos por biocatalizadores enzimáticos

Abstract

The textile industries produce large volumes of effluents with high organic charge and staining. It is estimated that 15-20% of the volume of dye added to the processes are discarded as waste. Dyes used for the textile industry have characteristics as resistance to light exposure and to many chemicals and will not discolor easily due to their complex structure and synthetic origin, which makes them difficult to be degraded it also have a toxic nature and impact in the environment. The application of enzymes as biocatalysts in the degradation of synthetic dyes is a promising alternative, considering that it is an environmentally friendly process, because enzymes are biodegradable, do not generate sludge and can mineralize more colorants, and has been shown to be effective in conducted in laboratory scale studies under various conditions. This work carried out laccase production optimization and testing by the liquid static culture at 28 ° C of Trametes sp. and Pycnoporus sp. in isolated culture and co-cultivation, using as cellulosic lignin residue rice husk in different particule sizes and masses. Crude enzyme extracts obtained were used in biodegradation of textile dyes Yellow Reactive HE4R and Black Reactive 5 in static regime (40 ± 2) ° C at different conditions of dye concentration and enzymatic activity with and without the presence of chemical mediator acid 4-hydroxybenzoic in two reaction media (aqueous and sodium acetate buffer). The use of the enzyme extract was efficient in the degradation of Reactive Black 5 dye for different conditions analyzed, but showed low efficiency in the degradation of the dye Reactive Yellow HE4R.