Biodegradation of diazo dye Evans blue by four strains of Streptomyces isolated from soils of Algeria

As part of the development of an ecological solution to eliminate azo dyes present in the effluents of textile factories, we have isolated from different soils four Streptomyces strains with high degra-dation potential against Evans blue (EB). These strains affiliated to Streptomyces maritimus, S. mu-tabilis, S. ardesiacus and S. sp can also degrade other azo dyes such as Amido black 10B, Chlorazol black E, Congo red, Methyl red and Nigrosine. Study of the effects of incubation time, tempera-ture, pH and addition of small amounts of carbohydrates on the degradation potential of strains allowed reaching an elimination rate of up to 97% of the initial Evans blue concentration (50 mg/ l). Furthermore, the degradation potential of strains was only slightly affected by high concentra-tions of EB, salinity and the presence of some metal ions in the culture medium.

Automated summary

In this study, four Streptomyces strains with high degradation potential against azo dyes were isolated from different soils. These strains, affiliated to Streptomyces maritimus, S. mutabilis, S. ardesiacus, and S. sp, were capable of degrading not only Evans blue but also other azo dyes. Through investigating the effects of incubation conditions, it was found that the degradation potential of the strains could be improved, and the strains showed minimal impact from high concentrations of azo dyes, salinity, and certain metal ions.