Evaluation of Light Irradiation on Decolorization of Azo Dyes by Tsukamurella sp. J8025

In the previous study, the dye decolorization was investigated by Tsukamurella sp. J8025 under the static condition at 30°C. The object of this study was to evaluate the influence of light irradiation with 15W low-pressure mercury lamp on dye decolorization. Three kinds of common culture medium Luria-Bertani (LB), Tryptic Soy Broth (TSB), and Yeast extract-Malt Extract (YEME) were used in this study. Strain J8025 was cultivated in different media added with methyl orange, and the rate of color removal was determined by measuring the absorbance at specific wavelengths. The experiments proved the decolorization efficiency after 48h under light irradiation in LB medium was up to 40%, that in TSB medium was up to 50%, and that in YEME medium was up to 68%, respectively. The decolorization process needed glucose as an energy source to support the bacterial growth and promote the decolorization rate. Due to the salt contained in the dye-wastewater, the effect of salt was investigated. The results showed nearly 98% color was removed after 48 h in the presence of 1% NaCl under light irradiation, but the decolorization was inhibited by high concentrations of salt. The results indicated a strain J8025 coupling with the light irradiation could be potentially used to improve the dye decolorization.