Biotechnology applied to the degradation of textile industry dyes

The presence of dyes in wastewater represents an environmental problem as this type of compounds cannot be eliminated through conventional methods of treatment. Biotechnology offers an alternative treatment, as most of the treatment systems based on chemical or physical methods are expensive and consume a great amount of energy and chemicals. This study mentions some conventional technologies together with a review of reports in which dyes have been degraded through biological methods. One of the advantages of this type of technologies is that a complete mineralisation of the dye can be achieved, apart from decolouration. There are a great number of microorganisms capable of eliminating colour in wastewater through mechanisms such as: biosorption, anaerobic or aerobic biodegradation and the production of enzymes that catalyse the decolouration process. One of the applications of biotechnology is the generation of new microbial strains that may constitute the basis of novel technologies for the remediation of xenobiotic compounds that are not easily degraded by conventional methods. Up to one decade ago, the identification of strains active in degradation was carried out through trial and error (successive rounds of mutagenesis and selection of mutants) or by selecting microorganisms adapted to polluted environments. The development of recombinant DNA technologies has generated new prospects for the optimisation of biotechnological processes for environmental treatments.