Experimental Investigation of Chlorella vulgaris and Enterobacter sp. MN17 for Decolorization and Removal of Heavy Metals from Textile Wastewater

The present study evaluated the performance of microalgae Chlorella vulgaris in an Enterobacter sp. MN17-assisted textile industry wastewater treatment system for decolorization, removal of heavy metals (Cu, Cr, Pb, and Cd), and chemical oxygen demand (COD). Different dilutions (5, 10, and 20%) of wastewater were prepared to decrease the pollutant toxicity for culturing microalgae and bacteria. Reduction of color, COD, and metal contents by microalgal treatment of wastewater varied greatly, while removal efficiency (RE) was significantly enhanced when endophytic bacterial strain MN17 inoculum was applied. Most notable, results were found at a 5% dilution level by Enterobacter sp. MN17-inoculated C. vulgaris medium, as chromium (Cr), cadmium (Cd), copper (Cu), and lead (Pb) concentrations were decreased from 1.32 to 0.27 mg L-1 (79% decrease), 0.79-0.14 mg L-1 (93% decrease), 1.33-0.36 mg L-1 (72% decrease), and 1.2-0.25 mg L-1 (79% decrease), respectively. The values of COD and color were also significantly decreased by 74% and 70%, respectively, by a C. vulgaris-Enterobacter sp. MN17 consortium. The present investigation revealed that bacterial inoculation of microalgae significantly enhanced the removal of coloring agents and heavy metals from textile wastewater by stimulating the growth of algal biomass. This study manifested the usefulness of microalgae-bacterial mutualism for the remediation of heavy metals, COD, and color in industrial effluents. Microalgae consortia with growth promoting bacteria could be a breakthrough for better bioremediation and bioprocess economy. Thus, further studies are needed for successful integration of microalgae-plant growth promoting bacterial (PGPB) consortium for wastewater treatments.