Abstract
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► Microalgal based decolorization and degradation of a dye, Rhodamine B. ► 18S rDNA analysis of efficient dye decolorizer. ► Degradation was confirmed by GC–MS analysis. ► By this biological procedure, toxic dye was decolorized and degraded from water.
In the present study a potential freshwater microalgae Coelastrella sp. was selected for degradation of synthetic dye, Rhodamine B in batch culture system. Effect of several physico-chemical parameters that influence the decolorization followed by degradation ability was investigated (inoculum concentration, initial dye concentration, temperature and pH) and optimal experimental condition was ascertained. The optimum operating conditions were found to be [Dye]=100mgl−1; [temperature]=30°C; with 10% of inoculum at a pH of 8. Under these conditions, a maximum of 80% decolorization of the dye was achieved in 20 days. Peroxidase activity of the isolate was also determined and it was found to be 2.1μmolminmg−1 of protein. The actual break down of the dye was confirmed by using various analytical techniques such as GC–MS, TLC, FTIR and UV–vis spectral analysis. Small aliphatic chains, small chain alcohols and ketones were obtained after degradation of Rhodamine B. These are the evidences that showed that microalgae play a vital role on dye degradation to non-toxic products effectively.