Decolorization and detoxification of textile dyes using a versatile Streptomyces laccase-natural mediator system

Abstract

Currently, there is increasing interest in assessing the potential of bacterial laccases for industrial and environmental applications especially in harsh conditions. The environmental impact of the textile industry requires novel and effective technologies to mitigate the presence of dyes in wastewaters before discharging into the environment. Dyes usually remain stable in the presence of a variety of chemicals, light and are recalcitrant to microbial degradation. Among available technologies the biological treatments offer environmentally friendly strategies for decolorizing and detoxifying these compounds. The recent discovery of versatile laccases in streptomycetes opens up new opportunities for their commercial application. The aim of this study is to assess the potential of a novel bacterial laccase SilA produced by Streptomyces ipomoeae CECT 3341 active over wide temperature and pH ranges for use as an eco-friendly, biological treatment for the degradation of textile dyes. Insights into the enhancement of the oxidative action of this enzyme through the use of natural redox mediators are presented together with an assessment of the potential toxicity of the degradation products. Our results confirm that the combination of the laccase and natural mediators such as acetosyringone and methyl syringate enhanced the decolorization and detoxification of a variety of textile dyes up to sixfold and 20-fold, respectively. Mediator concentration was found to have a significant effect (p < 0.05) on dye decolorization at 60 °C; thus, the decolorization of Acid Orange 63 increased from 6 to 70-fold when the mediator concentration was increased from 0.1 to 0.5 mM. Further, the toxicity of tartrazine decreased 36-fold when the SilA-MeS system was used to decolorize the dye. The thermal properties of the SilA coupled with the stability of SilA at high pH suggest a potential commercial application for use in the decolorization of textile wastewaters which generally are performed at high temperature (>55 °C) and salinity and neutral pH, conditions which are unfavourable for conventional fungal laccases.

Laccase-Enzyme Treated Flax Fibre for Use in Natural Fibre Epoxy Composites

“…Laccase is abundant in nature and sustainable. Besides, it is available in sufficient quantities and robust enough to be used in numerous industrial processes, e.g., in the food industry for processing and stabilizing beverages and additives in baking [ 25 , 26 ], for decolourisation and degradation of dyes in the textile industry, for pollution control in water and soil [ 17 , 27 , 28 , 29 , 30 ] as well as for pulp bleaching in the pulp and paper industry [ 24 , 31 , 32 ].…”

Environmentally Friendly and Recyclable Natural-Mediator-Modified Magnetic Nanoparticles for Laccase-Catalyzed Decolorization

“…e oxidized radical form of the SA is able to oxidize a wide range of substrates, including compounds with a high redox and/or nonphenolic compound. Previous research has reported that phenolic compounds related to lignin have shown their capability and efficiency to act as Journal of Chemistry natural Lac mediators [37]. Although ABTS and HBT are well-known arti cial redox mediators for Lac, these mediators are not economically feasible.…”

Identification and Characterization of New Laccase Biocatalysts from Pseudomonas Species Suitable for Degradation of Synthetic Textile Dyes

“…Metal ions such as Cu +2 , Ca +2 , Ni +2 , Co +2 , and Mn +2 are generally known to accelerate laccase activity at a remarkable level [13].Due to broad substrate spectrum, laccases have become very attractive for a variety of biotechnological and industrial applications such as organic synthesis; lignin degradation; and bio-product formation for the food, textile, and pharmaceutical industries; remediation of contaminated environments; as well as construction of biosensors and biofuel cells [14][15][16]. During the last decade laccases have been used in decolorization and detoxification of textile effluents [17]. Effluents from the textile industry are usually complex, containing a wide variety of synthetic dyes [18], among which the most common are azo dyes, anthraquinone, triphenylmethane, and indigo dyes [19].In the recent years, development of high-performance recombinant bacterial strains and the possibility of increasing the production of recombinant proteins created new opportunities for the commercial use of laccases, since the production from wild type strains has limitations in growth and product yield, which are not suitable for standard industrial fermentations [20].…”

“…Due to broad substrate spectrum, laccases have become very attractive for a variety of biotechnological and industrial applications such as organic synthesis; lignin degradation; and bio-product formation for the food, textile, and pharmaceutical industries; remediation of contaminated environments; as well as construction of biosensors and biofuel cells [14][15][16]. During the last decade laccases have been used in decolorization and detoxification of textile effluents [17]. Effluents from the textile industry are usually complex, containing a wide variety of synthetic dyes [18], among which the most common are azo dyes, anthraquinone, triphenylmethane, and indigo dyes [19].…”