Comparative analysis of dye decolorization efficiency and growth kinetics of microalgae in the presence of Methyl orange and Rhodamine B dye

Textile industries are the major contributor to water pollution due to the usage of highly toxic synthetic dyes. Synthetic dyes are non-biodegradable and toxic in nature and, pose significant ecological and health risks. Therefore, this study explores the impact of two prevalent dyes, Rhodamine B (RB) and Methyl Orange (MO), on microalgal growth and their decolorization efficiency. The study reveals differential effects, with RB exhibiting greater toxicity to microalgae compared to MO. Highest biomass growth was observed at 30 and 10 mg/L of MO and RB was 969.5 ± 38.2 µg/mL and 729.9 ± 73.9 µg/L respectively. Moreover, decolorization efficiency was highest in 10 mg/L of dyes, whereas it was highest in the presence of MO dye (54.6 ± 1.3%) compared to RB. Microscopic and spectroscopic analyses provide insights into morphological changes and surface interactions between microalgae and dyes. These findings underscore the potential of microalgae in dye removal, with implications for wastewater treatment and by-product generation.