Antimicrobial, anti-biofilm, and anti-proliferative activities of lipopeptide biosurfactant produced by Acinetobacter junii B6.

Lipopeptide biosurfactants (LPBs) are amphiphilic compounds produced by microorganisms exhibiting various biological activities. The main aim of the present study was to assess the in vitro antimicrobial, anti-biofilm, and cytotoxic effects of LPB produced by Acinetobacter junii (Aj L). We determined Aj L minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative bacteria as well as two fungal strains. Also, the anti-biofilm activity of Aj L against the biofilm produced by clinically isolated bacterial strains was investigated. The Aj L non-selectively showed activity against both Gram-positive and Gram-negative bacterial strains. The obtained results of the present study exhibited that the Aj L in concentrations nearly below critical micelle concentration (CMC) has an effective antibacterial activity. It was found that the MIC values of Aj L were lower than standard antifungal and it exhibited nearly 100% inhibition against Candida utilis. The attained results of the biofilm formation revealed that Aj L disrupted the biofilm of Proteus mirabilis , Staphylococcus aureus , and Pseudomonas aeruginosa at 1250 μg/ml and 2500 μg/ml concentrations. The attained results of cytotoxic effect (determined by WST-1 assay) of the Aj L revealed IC 50 of 7.8 ± 0.4 mg/ml, 2.4 ± 0.5 mg/ml, and 5.7 ± 0.1 mg/ml, against U87, KB, and HUVEC cell lines, respectively. The results indicated that Aj L has a potential application in the relatively new field of biomedicine. • The produced lipopeptide biosurfactant of A. junii B6 (Aj L) showed MIC of 5 μg/ml. • The Aj L disrupted the biofilm formed by clinical isolates of three bacterial pathogens. • The calculated IC 50 of Aj L against HUVEC cell line was found to be 7.8 ± 0.4 mg/ml. [ABSTRACT FROM AUTHOR]