Utilizing Pollutant Waste Cheese Whey into Low-cost Broth for Bacterial Growth and Protein Production

Cheese whey (CW), an abundant and nutrient-rich byproduct of cheese production, accounts for approximately 85% of milk volume and is generated globally in quantities reaching 145–200 million tons annually. Despite its biochemical complexity and high organic load, CW remains underutilized in microbial biotechnology. Its pollutant potential is up to 100 times higher than domestic sewage due to extreme biological oxygen demand (BOD), chemical oxygen demand (COD), high nutrient content, and acidity. Untreated discharge causes severe oxygen depletion, damages aquatic ecosystems, degrades soil, and contributes to climate change. This study evaluates CW as a sustainable and cost-effective alternative to synthetic bacterial growth media. Ten bacterial strains were cultured for 17 h in different forms of CW fresh, aged (up to two years), and dried and compared with standard Luria Bertani (LB) medium. Bacterial growth was assessed using optical density at 600 nm (OD₆₀₀), and protein yields were measured in µg/µL. CW supported growth ranged from OD₆₀₀ 2.36–4.46, comparable to 2.53–4.16 in LB, with protein yields between 0.19 and 0.43 µg/µL versus 0.18–0.44 µg/µL in LB. These findings demonstrate that CW can effectively support bacterial proliferation and protein production, offering a novel valorization route for a major agro-industrial pollutant while reducing environmental harm and fermentation costs.