The anticancer activity of two novel microbial lipopeptide biosurfactants, amphisin and viscosinamide, was evaluated against human (A375) and murine (B16 4A5) melanoma cells. Normal human dermal fibroblasts (NHDFs) were used as a control. Cell viability was assessed using the MTT assay, while membrane integrity was analysed by the lactate dehydrogenase (LDH) release test. Early and late stages of apoptosis were investigated using Annexin V-FITC and Hoechst 33342 staining, respectively. In addition, the expression of apoptosis-related genes bax and bcl-2 was quantified by RT-qPCR. Finally, the wound healing (scratch) assay was performed to evaluate the effect of the tested lipopeptides on the migratory ability of melanoma cells. Both lipopeptides inhibited melanoma cell proliferation in a concentration- and time-dependent manner and exhibited significantly lower cytotoxicity toward NHDF cells, indicating selective antitumor activity. Viscosinamide exhibited stronger cytotoxic activity than amphisin. LDH release and fluorescence microscopy confirmed that the main mechanism of cytotoxicity was cell membrane damage and induction of apoptosis, including phosphatidylserine externalization and characteristic changes in the cell nucleus, such as chromatin condensation and cell nucleus fragmentation. Gene expression analysis demonstrated increased levels of bax and decreased levels of bcl-2, indicating activation of the intrinsic mitochondrial pathway of apoptosis. In addition, tested compounds effectively inhibited cell migration. The studies show that amphisin and viscosinamide exhibit selective anticancer potential related to the cell membrane and are promising molecules for further development as melanoma treatments.

Quaternary ammonium surfactants, due to their diverse chemical structure and their biological properties, can be used in medicine as DNA carriers, disinfectants, and antimicrobial and antitumor agents. In this study, using melanoma A375, colon adenocarcinoma HT-29 and normal human dermal fibroblast (NHDF) cells, we tested the hypothesis that the quaternary ammonium surfactants 2-dodecanoyloxyethyl)trimethylammonium bromide (DMM-11), 2-dodecanoyloxypropyl)trimethylammonium bromide (DMPM-11) and 2-pentadecanoyloxymethyl)trimethylammonium bromide (DMGM-14) act selectively against cancer cells. The results showed that these compounds led to the initiation of the apoptotic process of programmed cell death, as evidenced by the ratio of the relative expression of Bax protein to Bcl-2. The encapsulation of surfactants in liposomes allowed lower concentrations to be used. Moreover, encapsulation reduced their toxicity towards non-cancerous cells. The anticancer efficiency and apoptotic effect of the liposomal formulations with surfactants (DMM-11, DMPM-11 and DMGM-14) were higher than those of surfactant-free liposomes. Therefore, quaternary ammonium surfactant-loaded liposomes show significant potential as delivery vehicles for the treatment of melanoma and colon cancers. The use of nano-formulations offers the advantage of optimizing quaternary ammonium surfactant delivery for improved anticancer therapy.

Biofilms formed by Candida albicans pose therapeutic challenges due to their resistance to conventional antimicrobials, highlighting the need for more effective treatments. Rhamnolipids (RLs) are biosurfactants with diverse antimicrobial properties. Bacteriophages are viruses that target specific bacterial strains. Recent studies have shown that they may affect biofilm formation by fungi and yeasts. This study investigated the combined antimicrobial effects of RLs and bacteriophages against C. albicans biofilms, focusing on their anti-adhesive and inhibitory effects on biofilm development. RT-PCR assays were used to analyze gene modulation in C. albicans biofilm formation in response to RLs and bacteriophage treatments, while hyphae formation was examined using microscopy. The results showed that RLs-bacteriophage combinations significantly reduced biofilm formation compared to individual treatments. A combination of 200 mg/L RLs with bacteriophage BF9 led to a 94.8% reduction in biofilm formation. In a subsequent model, the same RL concentration with bacteriophage LO5/1f nearly eliminated biofilm formation (~96%). Gene expression analysis revealed downregulation of key biofilm-associated genes when Candida cells were treated with 200 mg/L RLs and four bacteriophages (BF17, LO5/1f, JG004, FD). These results show the potential of RL and bacteriophage combinations in combating C. albicans biofilms, presenting a promising therapeutic approach against resilient infections.

Biosurfactants are environmentally friendly surface-active compounds with promising applications in environmental remediation. In this study, a biosurfactant-producing bacterium, Bacillus (B.) velezensis SHB.28, was isolated from heavy metal-contaminated soil and evaluated for its ability to produce biosurfactants using date syrup as a low-cost agro-industrial substrate. Screening assays including drop-collapse (DC), oil spreading (OS), and emulsification index after 24 h E₂₄ (%) confirmed strong biosurfactant production. Culture conditions were optimized, revealing that 30 °C, pH 6, and a C/N ratio between 10% and 20% provided optimal production. Under optimized conditions, the crude biosurfactant extract yield reached 2.16 g/L within 24 h, accompanied by a reduction in surface tension from 69 to 29.1 dyn/cm and high emulsification activity. Kinetic modeling showed that emulsification activity followed an exponential growth model (R² = 0.985), whereas surface tension dynamics were well described by a spike decay–plateau model (R² = 0.998). Structural characterization using Fourier-transform infrared spectroscopy (FTIR), electrospray ionization–mass spectrometry (ESI–MS), and nuclear magnetic resonance (NMR) spectroscopy revealed that the biosurfactants are surfactin- and iturin-like cyclic lipopeptides composed of a β-hydroxy fatty acid chain (C₁₃–C₁₅) linked to a cyclic peptide moiety. The biosurfactant exhibited a critical micelle concentration of 100 mg/L and an anionic character with a pHpzc of 5.7. Furthermore, it demonstrated high efficiency in removing heavy metals, achieving removal efficiencies of 99.88% for Fe²⁺, 99.69% for Pb²⁺, and 94.72% for Cu²⁺, outperforming conventional surfactants such as SDS and Tween 80. These findings highlight the potential of date syrup-derived surfactin and iturin from B. velezensis SHB.28 as sustainable and efficient biosurfactants for environmental remediation and heavy metal removal applications.