Bioremediation of Crystal Violet and Malachite Green Dyes by Some Algal Species

Abstract

IOLOGICAL treatment of crystal violet and malachite green ……using blue-green algae (Nostoc sp., Microcystis aeruginosa and Oscillatoria geminata) and green algae (Chlorella vulgaris and Scenedesmus sp.) in order to assess the decolorization ability of these algae after incubation for 2 and 24 hr in three dyes concentrations at 10, 50 and 100 ppm. Chlorella has achieved the highest percentage of crystal violet decolorization after 2 hr at 10 ppm, but after 24 hr Scenedesmus gave the highest percentage of decolorization at 10 ppm. The highest proportion of malachite green decolorization after two hours using Chlorella at 50 ppm, but after 24 hr the higher decolorization percentage of malachite green obtained by M. aeruginosa at 100 ppm followed by Scenedesmus sp. at the same concentration. The green algae showed a high capacity for crystal violet decolorization than blue-green algae. Measuring the activity of laccase, manganese peroxidase and tyrosinase enzymes indicated that Nostoc sp. gave the highest laccase activity in all dyes concentrations, while the other two enzymes haven't any activity. Chlorophyll-a and phaeophytine-a values obtained showed significant differences between most treatments; the most negatively affected species was O. geminata which showed decreasing in chl-a content in the two dyes concentrations. In conclusion; the decolorization process of dyes by algae had been done by different mechanisms; one of them was enzymatic degradation as Nostoc sp. C. vulgaris and Scenedesmus sp. have a high ability to decolorize the two dyes so they might be used in wastewater treatment of fish farms contains these carcinogenic dyes as antifungal agents.