Isolation and characterization of <i>lactobacillus</i> and <i>bacillus</i> producing biosurfactants

Abstract

This study focuses on the screening, production, extraction of biosurfactants from Lactobacillus and Bacillus, and its antimicrobial properties against causal microorganisms of food borne infection (food borne pathogens). The biosurfactants were investigated for potential antimicrobial activity using disk diffusion method against causal organisms of food borne illnesses. These food borne pathogens include Salmonella typhi, Escherichia coli, Staphylococcus aureus, Salmonella paratyphi and Shigella dysentrae. Biosurfactant producing isolates were identified using blood haemolysis test, oil spreading technique and drop collapse assay. Emulsification assay of positive isolates was performed at pH 4, 6, 8, 10), temperatures 4ºC, 25ºC, 37ºC), NaCl concentrations (4%,6%,8%,10%), different sources of carbon (glucose, sucrose) and nitrogen sources - urea, yeast.

Keywords: Biosurfactants, Lactobacillus, Bacillus, Emulsification