The textile industry generates a substantial quantity of wastewater containing carcinogenic and mutagenic dyes, posing significant environmental risks. Using microalgae to remove dyes from wastewater offers an eco-friendly solution to this issue. Accordingly, this study aimed to characterize textile wastewater and evaluate the potential of Chlorella sorokiniana strain HIN-3 for dye removal. Twenty textile wastewater samples were analyzed for pH, electrical conductivity, total dissolved solids (TDS), chlorides, cadmium, lead, chromium, nickel and color. The ability of strain HIN-3 to biodegrade seven structurally distinct dyes was investigated. The effects of metals (cadmium, lead and copper), TDS (1300–5200 mg L−1) and nitrogen sources (NaNO3, NH4Cl and urea) on dye degradation were evaluated. Additionally, six dye-rich industrial effluents were treated with microalgae for dye removal, and the activities of dye-degrading enzymes were measured. Results revealed that 25%, 50%, 55% and 100% of the samples exceeded Pakistan's National Environmental Quality Standard (NEQS) limits for pH, TDS, chlorides and dye content, respectively. The decolorization ability of strain HIN-3 varied between 8 and 87% across seven dyes. TDS levels up to 3900 mg L⁻1 did not affect the decolorization of Congo Red; however, higher TDS levels reduced its efficiency. Similarly, lead and cadmium at 1 mg L⁻1 had no significant impact, but contamination at 5 mg L⁻1 decreased decolorization. Among the nitrogen sources tested, urea achieved the highest decolorization rate of 92%. Additionally, strain HIN-3 decolorized 22–65% of the dye-rich textile effluents. The observed decolorization of the dyes was attributed to the activity of dye-degrading enzymes, including laccase, lignin peroxidase and manganese peroxidase. Thus, due to its high decolorization efficiency in the presence of salts and metals, strain HIN-3 shows great potential for the treatment of textile wastewater. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.
