Extraction and purification of biosurfactant by locally isolated Enterococcus faecium bacteria and study of its antimicrobial activity

Abstract

In this research, the biosurfactant production by Enterococcus faecium isolated from Raw cow's milk was studied when growing in the MRS medium containing Lactose as a carbon source without Tween-80. E.faecium supernatant exhibited emulsion action of 60% towards kerosene oil as oil in water, while the surface activity was 34 mm. Biosurfactants with surface tension activity properties were extracted and partially purified from E. faecium by cold acetone 3:1, The chemistry structure of the biosurfactant was analyzed, which indicated that it is a glycol-lipo-peptide. Biosurfactant that purified from E. faecium showed antibacterial activity by reducing growth of several pathogenic G-ve and G+ve bacteria, including aureus, Staphylococcus epidermidis, Streptococcus sp., Staphylococcus Escherichia coli, Klebsiella sp., Pseudomonas aeroginosa, Acinetobacter sp. and Serratia sp. The inhibitory activity of biosurfactant against pathogenic bacteria was studied by using agar diffusion method, where the biosurfactant had higher inhibitor activity against E. coli, where highest diameter of inhibition zone was (23mm). At all concentrations examined, a biosurfactant derived from E. faecium considerably decreased bacterial adhesion, albeit to a lower amount. Keyword: Enterococcus faecium, LAB, Biosurfactant, Antibacterial and Antiadhesive activity.