Characterization of a newly isolated biosurfactant fengycin produced by Heyndrickxia coagulans strain

One of the major global concerns in human and veterinary medicine at present is the antimicrobial resistance to conventional antibiotics. Natural products from microbial sources appear to be the most favorable alternative to current antibiotics. Biosurfactants (BSs) are surface-active compounds synthesised by a wide variety of microorganisms. Fengycin is an important member of the lipopeptide family, with a wide range of applications in different industries and a broad spectrum of antimicrobial activity against pathogenic microbes. The production of fengycin has been detected in various strains of Bacillus spp., but to our knowledge, not in Heyndrickxia coagulans. Strain H. coagulans (formerly known as B. coagulans) Biocenol™ 9FT27 CCM 9014, which exhibited surfactant activity as assessed by oil spreading assay, was characterised using the 16S rRNA sequencing method. PCR screening detected the presence of fenD, indicating the production of the lipopeptide biosurfactant fengycin. The results of UHPLC-DAD, NMR and MALDI-TOF/MS analysis confirmed the production of fengycin by H. coagulans 9FT27. BS was found to significantly (P < 0.0001) inhibit the biofilm formation of Staphylococcus aureus CCM 4223 and MRSA (methicillin-resistant Staphylococcus aureus) at concentrations ranging from 15 to 0.2 mg/mL. Analysis of qRT-PCR results revealed reduced expression of the srtA, gyrB, clfB and icaADB operon genes, which are associated with biofilm formation. Our results indicate the potential of fengycin in the control of biofilm-related infections, especially those caused by antibiotic-resistant S. aureus strains.