Glycolipopeptide biosurfactants from Serratia marcescens exhibit broad-spectrum antimicrobial activity for sustainable biocontrol of multidrug-resistant pathogens.

Abstract

The rising prevalence of multidrug-resistant (MDR) pathogens across clinical, agricultural, and environmental settings underscores the urgent need for alternative antimicrobial agents. In this study, biosurfactants produced by Serratia marcescens were extracted, isolated, and characterized to assess their broad-spectrum antimicrobial potential. The S. marcescens-derived biosurfactant (SMBS) demonstrated strong surface activity, confirmed through oil spreading (19.4 mm), drop collapse, and a high emulsification index (%E24 of 74.8% with olive oil). Structural characterization using HPTLC, FTIR, and GC-MS suggested that SMBS is a complex glycolipopeptide comprising lipid, peptide, and carbohydrate moieties. Functionally, SMBS exhibited considerable antibacterial activity with inhibition zones of 12 mm, 11 mm, and 14 mm against Acinetobacter pittii, Proteus vulgaris, and Staphylococcus aureus, respectively. Antifungal assays revealed notable inhibition of Aspergillus niger (2 mm) Candida albicans (6 mm), Fusarium proliferatum (16 mm), and Penicillium purpurogenum (20 mm). While SMBS showed significant activity, it was comparatively less effective than streptomycin in most cases. These findings highlight the potential of SMBS as a sustainable, multifunctional biocontrol agent suitable for use in healthcare, agriculture, and environmental management. Its broad-spectrum efficacy, structural complexity, and biodegradability offer an attractive alternative to conventional antimicrobials. However, challenges such as large-scale purification, production cost, and the need for detailed toxicity and mechanism-of-action studies remain. Addressing these aspects will be essential for advancing SMBS toward clinical and commercial applications.