The objective was to evaluate the capacity of Lactiplantibacillus plantarum LP5r to improve the microbiological and physicochemical quality of wastewater from a dairy company. Lactiplantibacillus plantarum LP5r was inoculated (8.8 log10 CFU g-1 mL-1) into 50 L containers of wastewater, 10 mL was added to T1, 10 mL to T2 with monthly replenishment, 50 mL to T3, and 50 mL to T4 with monthly replenishment. The CT was kept without inoculum. Initially, L. plantarum LP5r showed values above 6 log10 CFU g-1. In T1 and T3 decreased to undetectable values, but in T2 and T4 remained above 4 log10 CFU g-1. Enterobacteriaceae were initially 5.46 log10 CFU g-1 and decreased to 4.88 and 4.73 log10 CFU g-1 for T2 and T4 and increased to 7.31 log10 CFU g-1 in CT. Coliforms were reduced from 7.38 log10 CFU g-1 to 2.95 and 2.11 log10 CFU g-1 in T2 and T4. Initial suspended solids were 19 997 mg L-1, which decreased to 6058.3 mg L-1 and 4118.9 mg L-1 for CT and T4. The pH did not differ between samples. An initial BOD5 of 7680 mg L-1 was detected in all samples, which decreased to 2385 mg L-1 for CT and 820 mg L-1 for T4, and the COD decreased from 17 827 mg L-1 to 4839 mg L-1 and 1649 mg L-1 for the CT and T4 samples. Lactiplantibacillus plantarum LP5 positively influences the microbiological quality and COD and BOD5 of the dairy's wastewater.
Keywords: BOD5; COD; coliforms; enterobacteria; probiotic; wastewater treatment.
© The Author(s) 2025. Published by Oxford University Press on behalf of Applied Microbiology International.