<p>This study investigates the synergistic potential of co-cultivating <i>Chlorella vulgaris</i> and <i>Scenedesmus obliquus</i> to optimize microalgal biomass production and enhance the removal efficiency of cadmium and copper ions. Co-culture experiments were conducted at different microalgal ratios, and the sample with the highest biomass concentration was selected for the biosorption experiments. Heavy metal ions were added separately to the algal suspension at its maximum optical density, and removal efficiency was measured using atomic absorption spectroscopy. The results demonstrated that a 1:1 species ratio significantly increased biomass concentration, reaching nearly 4 g L⁻¹. The biosorption capabilities of the microalgal co-culture were also assessed, revealing impressive removal efficiencies for heavy metals, with cadmium being more readily accumulated than copper. Maximum removal percentages of 66.77% for cadmium and 68.38% for copper were recorded at lower metal concentrations, indicating the potential of the co-culture system for bioremoval applications. However, increased metal concentrations adversely impacted removal efficiency, likely due to the formation of metal complexes that hinder metabolic processes. FTIR analysis identified characteristic functional groups involved in the biosorption process, confirming the significance of carboxyl groups in binding heavy metal ions. Initially, the rapid uptake of metal ions was driven by electrostatic interactions and complexation. As biosorption progressed, it transitioned to chemisorption, revealing limitations due to the availability of active sites on algal cells at higher concentrations. The differential absorption efficiencies for cadmium and copper further illustrate the complexities of microalgal interactions with heavy metals, with copper-induced oxidative stress negatively affecting algal growth and biosorption capacity.</p>