The wastewaters of nejayote and food waste leachate are polluting effluents with a high load of organic matter that cause great problems when discharged to water receptors. In this work, we investigated the treatment of nejayote wastewaters and food waste leachate for the production of microalgae Scenedesmus acutus and Haematococcus pluvialis. For Scenedesmus acutus, treatment with 10% food waste leachate and 90% growth medium resulted in a concentration of 5.34 g/L in 20 days (μmax = 0.16/day). Meanwhile, 10% nejayote and 90% medium growth produced 4.45 g/L at 20 days (μmax = 0.13/d). A significant reduction of up to 82.6% ammonium, 84.1% orthophosphate, and 87.25% COD was also observed between the different treatments. For Haematococcus pluvialis, the treatment of 90% food waste leachate and 10% growth medium produced a concentration of 4.73 g/L at 6 days (μmax = 0.71/day), while the mixture of 25% najayote, 25% food waste leachate, and 50% growth medium produced a concentration of 5.5 g/L at 20 days (μmax = 0.25/dat). A reduction of up to 97.8% ammonia, 97.4% orthophosphate, and 73.19% COD was also recorded. These findings demonstrated the potential to cultivate microalgae and extract biomolecules for commercial purposes.

Livestock wastewater represents both an environmental challenge and a potential nutrient source for microalgal bioprocesses. This study developed a sequential upstream–downstream strategy integrating wastewater-based cultivation of Chlorella vulgaris with ultrasound-assisted carotenoid recovery. A simplex-centroid mixture design was first used to evaluate slaughterhouse wastewater, swine wastewater, and Bold’s Basal Medium as cultivation components. Within the investigated mixture domain, 100% swine wastewater produced the highest cell concentration, with predicted and experimentally validated values of 5.08 × 10⁶ and 5.41 × 10⁶ cells mL⁻¹, respectively. Nutrient removal reached up to 97% for NH₄⁺–N, 40% for PO₄³⁻–P, and 92% for COD, depending on wastewater formulation. Subsequently, ultrasound-assisted carotenoid extraction was optimized using response surface methodology. The model-selected operating condition was 25% amplitude and 10 min; experimental testing yielded a spectrophotometric lutein-equivalent content of 116.80 mg kg⁻¹ and an extract purity index of 2.39, compared with model estimates of 118.47 mg kg⁻¹ and 2.42, respectively. The study demonstrates the laboratory-scale feasibility of experimentally linking wastewater formulation with subsequent pigment recovery while identifying analytical, energetic, and scale-up limitations requiring further investigation.