Newly Antibacterial and Antiadhesive Lipopeptide Biosurfactant Secreted by a Probiotic Strain, Propionibacterium Freudenreichii

Abstract

A lipopeptide biosurfactant production from a probiotic type strain of Propionibacterium freudenreichii subsp. freudenreichii is being reported here for the first time. This biosurfactant is able to reduce the surface tension of water from 72 to 38 mN/m with an increase of the biosurfactant concentration up to critical micelle concentration value of 1.59 mg/ml. The production of the biosurfactant was found to be much higher in medium containing sunflower oil compared to the glucose-containing medium. The maximum emulsifying activity (E24 = 72 %) was attained with used frying sunflower oil, while kerosene and starch had the lowest emulsifying activity. Biosurfactant production seems to be parallel to cell growth. The produced biosurfactant was relatively thermo-stable and no appreciable changes in biosurfactant activity occurred at temperature ranges of 25–85 °C. The analysis of the extracted biosurfactant by thin layer chromatography, infrared spectroscopy, and 1H and 13CNMR spectroscopy revealed the chemical nature of the biosurfactant as lipopeptide. Produced lipopeptide was evaluated for its antimicrobial and antiadhesive activity and showed significant antimicrobial and antiadhesive action against a wide range of pathogenic bacteria and fungi. A total growth inhibition was observed over Rhodococcus erythropolis, while the best result of antiadhesion was obtained against Pseudomonas aeruginosa.