Adaptation and Bioremediation Efficiency of UV-Mutagenized Microalgae in Undiluted Agro-Industrial Effluents from Mexico

Microalgae offer a sustainable alternative for wastewater treatment by simultaneously removing pollutants and producing biomass of potential value. This study evaluated five species—Haematococcus pluvialis, Chlorella vulgaris, Chlamydomonas sp., Anabaena variabilis, and Scenedesmus sp.—in three undiluted food and beverage industry effluents from Mexico: nejayote (alkaline wastewater generated during corn nixtamalization for tortilla production), tequila vinasses (from tequila distillation), and cheese whey (from cheese making). Strains were adapted through UV mutagenesis and gradual acclimatization to grow without freshwater dilution. Bioremediation efficiency was assessed via reductions in chemical oxygen demand (COD), total nitrogen (TN), and total phosphates (TPO4). C. vulgaris achieved complete TN and TPO4 removal and 90.2% COD reduction in nejayote, while A. variabilis reached 81.7% COD and 79.3% TPO4 removal in tequila vinasses. In cheese whey, C. vulgaris removed 55.5% COD, 53.0% TN, and 35.3% TPO4. These results demonstrate the feasibility of microalgae-based systems for treating complex agro-industrial wastewaters, contributing to sustainable and circular wastewater management.