Biodegradation of dyes by some green algae and cyanobacteria

The ability of Chlorella vulgaris, Lyngbya lagerlerimi, Nostoc lincki, Oscillatoria rubescens, Elkatothrix viridis and Volvox aureus to decolorize and remove methyl red, orange II, G-Red (FN-3G), basic cationic, and basic fuchsin was investigated. These algae showed different efficiency for colour removal; varied from ∼4 to 95% according to the algal species, its growth state and the dye molecular structure. Basic cationic and basic fuchsin were the most susceptible dyes for decolorisation and removal by all algae being tested, and up to ∼82% of methyl red was also removed by N. lincki and O. rubescens. However, the algal activity to decolorize orange II and G-Red was markedly fluctuated and lower. C. vulgaris displayed activity to remove ∼43.7 and 59.12% while as V. aureus removed 5.02 and 3.25% of the added dyes respectively. The results also showed that treatment of either C. vulgaris or N. Linckia with G-Red or methyl red, respectively, induced the algal azo dye reductase enzyme by 72 and 71% at the same order. © 2009 Elsevier Ltd. All rights reserved.