Characterization of Biosurfactant Produced by Probiotic Bacteria Isolated from Human Breast Milk

Laya Tabrizi Rayeni,Shahla Soltani Nezhad

doi:10.15171/ijbsm.2018.04

Abstract

Background: Breast milk is an important nutrient source for rapidly growing neonates since breastfeeding protects the newborn against some disease. 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 producing 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 rDNA gene sequencing analysis. In vitro antibacterial activities of biosurfactants against some Gram-positive and Gram negative bacteria were investigated by the agar disc diffusion method. This biosurfactant was characterized with 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, Pediococcus pentosaceus HM-2 and Pediococcus pentosaceus HM-3 based on microscopic and 16S rDNA gene sequencing analysis. The biosurfactant extracted from screened strains exhibited a broad spectrum of antagonistic activity against some pathogenic bacteria. The results showed similarity to lipopeptide biosurfactants like surfactin. Conclusion: Bacterial strains isolated in this study could be valuable sources for novel biosurfactants. The Human breast milk could be a safe source for isolation of biosurfactant producing probiotic bacteria and for improve intestinal microflora of infants.

Highlights

Breast milk is an important nutrient source for rapidly growing neonates since breastfeeding protects newborns against a variety of diseases
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 Human breast milk is a safe source for obtaining biosurfactant producing probiotic bacteria and for improving gut microflora of infants

Summary

Introduction

Breast milk is an important nutrient source for rapidly growing neonates since breastfeeding protects newborns against a variety of diseases. Human breast milk is the best food for infants because it fulfills all the nutritional requirements for them, ; it educates the infant immunity functions and confers a certain degree of protection against infectious diseases.[1] These effects seem a result of the action of many bioactive molecules, present in breast milk, including different antimicrobial compounds, immunoglobulins, and immune cells.[2,3] The breast milk contains prebiotic substances that preserve the beneficiary bacteria in the infant gut.[3,4] Human breast milk is constituted from several bacterial species, such as Staphylococci, Streptococci, Micrococci, Lactobacilli, Enterococci, Lactococci and Bifidobacteria.[5,6] Biosurfactants are heterogeneous amphipathic surface active molecules that belong to a wide range of chemical classes These are mostly excreted by microorganisms outside the cells, and in some cases attached to the cells.[7] Microbial biosurfactants produced by a wide variety of microorganisms, have a lower toxicity and a higher biodegradability than chemical surfactants. Microbial surfactants play an important role in a wide variety of industrial and biotechnological applications such as agriculture, foodprocessing, cosmetics and medical fields as antibacterial, antifungal and antiviral

Methods

Results

Conclusion