Production, chemical characterization and bioactive properties of cell-bound and extracellular biosurfactants from a newly isolated, potential probiotic Lactobacillus strain grown on dairy wastes

The use of health-promoting microorganisms for biosurfactant (BS) production could expand their applications, especially in novel food formulations. This study investigated fourteen newly isolated lactic acid bacterial strains for their ability to produce cell-bound (CB) and extracellular (EC) BS using deproteinized cheese whey (CW) as substrate. Among the tested isolates, the potential probiotic strain Lactiplantibacillus plantarum F254 showed the most promising results in terms of substrate utilization and BS production. In batch bioreactor fermentations with CW as the sole nutrient source, the strain was able to produce 0.25 g/L of cell-bound BS (CB-BS) and 0.51 g/L of extracellular BS (EC-BS). Critical micelle concentration (CMC) was lower for CB-BS (0.20 g/L) compared to the EC-BS (1.07 g/L). ATR-FTIR and chromatographic analyses point to a glycolipopeptide nature for both BS types composed mainly of glucose, galactose, and palmitic acid; however, amino acid profiles differed: CB-BS contained predominantly arginine and glutamic acid, while EC-BS were mainly composed of phenylalanine, isoleucine, and proline. Both BS types were also able to inhibit several pathogenic microorganisms, while EC-BS could completely suppress the growth of Staphylococcus aureus . This is the first report describing simultaneous production and characterization of both CB and EC-BS by L. plantarum F254. The ability to obtain bioactive BS from a potential probiotic strain using dairy waste as substrate demonstrates clear bioprocess and industrial relevance, providing a sustainable route for valorizing CW while generating natural compounds suitable for clean-label food formulations or other high-value applications. • Investigation of novel lactic acid bacteria isolates for biosurfactant production. • Production of cell-bound and extracellular biosurfactants using cheese whey • ATR-FTIR analysis indicated a glycolipopeptide-type of biosurfactants • Individual component analysis of cell-bound and extracellular biosurfactants • Extracellular BS could completely inhibit the growth of Staphylococcus aureus