Isolation and structural characterization of Coryxin, a novel cyclic lipopeptide from Corynebacterium xerosis NS5 having emulsifying and anti-biofilm activity

• Production of a new lipopeptide biosurfactant by C. xerosis is reported.
• Structure of this new cyclic lipopeptide biosurfactant, coryxin, is characterized.
• Coryxin is a more efficient emulsifier than chemical surfactant such as Tween 80.
• Coryxin has anti-adhesive activity for efficient removal of biofilms.

Herein we reported the structure and several properties of a new biosurfactants produced by Corynebacterium xerosis strain NS5. This strain was capable of producing a novel lipopeptide biosurfactant that we have named coryxin. The biosurfactant structure was characterized by using Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (NMR), and Liquid chromatography-mass spectrometry (LC–MS). It contained a hydrophobic moiety of 3-hydroxydecanoic acid and a peptide part predicted as a sequence of seven amino acids including Asn–Arg–Asn–Gln–Pro–Asn–Ser. Coryxin lowered the surface tension of water to 31.4 mN/m, with a critical micelle concentration of 25 mg/l. It was a strong emulsifier with an emulsification index of 61% against n-hexane. Coryxin showed antibacterial activity against test organisms belonging to Gram-positive and Gram-negative bacteria and disrupted preformed biofilms of Staphylococcus aureus (82.5%), Streptococcus mutans (80%), Escherichia coli (66%) and Pseudomonas aeruginosa (30%). In conclusion, microbial surfactant from C. xerosis exhibited inhibitory and disruptive activities against biofilm formation that could be of use in biofilm-related menace.

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