Cyanobacterial phycoremediation: a sustainable approach to dairy wastewater management

The dairy industry is a significant sector within the food industries, known for its high-water consumption and consequent generation of dairy wastewater (DWW), which is rich in pollutants like Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). Improper disposal of DWW poses serious environmental challenges, including eutrophication and highlighting the need for sustainable biological treatment methods. This study investigates the potential of indigenous cyanobacterial strains Oscillatoria pseudogeminata, Oscillatoria proteus, Oscillatoria trichoides, and Lyngbya ceylanica for the bioremediation of DWW. Under controlled laboratory conditions, these strains were assessed for their uptake capabilities for 15 days. Results indicated that L. ceylanica significantly reduced (approx. 70%, P < .05) in key pollutants such as ammonia, nitrate, and phosphate compared to other strains. Biochemical analyses indicated a decrease in biomass, chlorophyll a, carotenoids, proteins, and carbohydrates in DWW relative to the growth of cyanobacteria in BG 11 media. This decline may hinder the effectiveness of cyanobacterial in wastewater remediation. The findings highlight the efficacy of selected cyanobacteria in nutrient removal from DWW, emphasizing their dual role in nutrient uptake through biosorption mechanism and biomass generation. The results pave the way for innovative biotechnological applications such as biofertilizers and feedstock for bioethanol/ biodiesel production, thus promoting more sustainable management practices within the dairy industry.