Abstract
Introduction: Breast milk is an important nutrient source for rapidly growing neonates since
breastfeeding protects newborns against a variety of diseases. This effect may be due to the
useful and natural microflora of breast milk. Biosurfactants are unique amphipathic compounds
produced by some microorganisms. The present study demonstrates the isolation and
characterization of biosurfactant generating bacteria from human breast milk samples.
Methods: The human breast milk samples were collected aseptically and then cultured in
MRS agar media. The biosurfactant producing ability of the isolated strains was investigated by
hemolytic assay, oil spreading method, drop collapse test and emulsification index assay. The
screened isolates were identified by 16S rRNA gene sequencing. In vitro antibacterial activities
of biosurfactants against a number of common bacterial strains were investigated by the agar
disc diffusion method. This biosurfactant was characterized by Fourier-transform infrared
spectroscopy (FTIR).
Results: In this study, 337 different colonies were isolated from 42 breast milk samples. The
best isolates were identified as Pediococcus pentosaceus HM-1, P. pentosaceus HM-2 and
P. pentosaceus HM-3 based on microscopic and 16S rRNA gene sequencing analysis. The
biosurfactant extracted from screened strains exhibited a broad spectrum of antagonistic activity
against some pathogenic bacteria.
Conclusion: Bacterial strains isolated here can be valuable sources for novel biosurfactants. The
Human breast milk is a safe source for obtaining biosurfactant producing probiotic bacteria and
for improving gut microflora of infants.