Proteolytic Activity of Bacillus cytotoxicus on Casein and Serum Proteins: A Pathway to Dairy Waste Treatment and Sustainability

The dairy industry has seen significant growth due to technological advancements that have improved milk production and the development of milk-based products. However, this growth has led to increased waste generation, which poses environmental challenges if not managed properly. Dairy wastewater contains high concentrations of organic materials, such as casein and serum proteins, necessitating effective and environmentally friendly treatment systems. Biological treatment methods, particularly those utilizing the proteolytic activity of bacterial strains, offer a promising solution due to their sustainability and efficiency. This thesis investigates the ability of Bacillus cytotoxicus strains, isolated from various sources including insects (9 strains) and potatoes (9 strains), to degrade key milk proteins, casein, and serum proteins, as a means of treating dairy wastewater. The strains were cultivated on selective media, and their proteolytic activity was assessed through halo formation on Milk Agar plates. In-vitro casein hydrolysis tests and spectrophotometric evaluations were conducted to measure bacterial growth and protein degradation. Additionally, protein concentrations post-degradation were analyzed using the Bicinchoninic Acid (BCA) assay, and the profile of protein degradation was evaluated through Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). The results revealed that Bacillus cytotoxicus strains successfully degraded both casein and whey proteins, demonstrating their potential for use in more sustainable and cost-effective dairy waste treatment solutions. Statistical analyses were performed to ensure the accuracy and validity of the findings. These results not only highlight the strains' potential environmental applications but also open up new possibilities for the valorization of dairy byproducts, contributing to a reduction in the environmental impact of dairy production processes.