Innovative bacterial consortia for simulated dairy wastewater treatment: improving COD removal efficiency

Dairy industry generates wastewater characterized by organic components, predominantly composed of proteins and fats, which can be effectively treated through biological processes. The present study aims to develop a bacterial consortium for bio-augmentation to enhance the treatment of simulated dairy wastewater. A total of 75 bacterial isolates were obtained using direct (DI) and enrichment-isolation (EI) methods. Among these, four strains exhibiting the highest proteolytic and lipolytic activities within 24 h were selected for further investigations. The isolates were screened based on their extracellular enzyme activities (proteinase and lipase), as well as their maximum lipolytic (0.3-0.7 mm/h) and proteolytic activity (0.67-0.83 mm/h) by a novel approach of rate of diffusion on TA and MSMA, respectively. The selected strains were identified by 16S rRNA gene sequencing as Massilia (DSSC1), Brevibacillus (ENAT1), Pseudomonas (ENOG5), and Lysinibacillus (ETOG2). The biodegradation potential of individual strains and their consortium was assessed through COD reduction in simulated dairy wastewater. The individual bacterial strains achieved COD reductions from an initial concentration of 3.82 g/L to 2.95, 2.81, 2.48, and 2.89 g/L. In contrast, bio-augmentation with the bacterial consortia reduced COD to 2.19 g/L, resulting in a 26-86% higher reduction compared to the individual strains. This study presents the first report on the use of a novel approach of diffusion-based assay to develop an effective and innovative bacterial consortium for efficient dairy wastewater treatment. These findings highlight the potential of this approach toward enhancing biodegradation efficiency and advancing sustainable wastewater management practice.