Biodecolorization of methyl orange by bacteria isolated from textile industrial wastes: optimization of cultural and nutritional parameters

Bioremediation of textiles wastewater contaminated with dyes has been widely described since their cost/efficiency ratios are lower than other physico-chemical processes. In the present study, effluent samples were collected from textile industries located in Settat city in Morocco, and were used for the isolation of bacterial strains that are able to decolorize the textile dye Methyl Orange. Physico-chemical properties of the effluent samples were analyzed and five bacterial strains S3, S4, S6, S7 and S8, capable of decolorizing Methyl Orange were screened and isolated. They showed more than 90% of decolorization activity at 37°C and at neutral pH. UV-Visible absorption spectra before and after decolorization showed significant change in the positions of peaks, when compared to control dye spectrum, indicating that decolorization was due to biodegradation.