CHARACTERIZATION OF THE PHYSICOCHEMICAL PROPERTIES OF THE BIOSURFACTANT PRODUCED BY L. ACIDOPHILUS AND L. PENTOSUS

Abstract

Biosurfactants or surface-active compounds are biodegradable, non-toxic and eco-friendly compounds released by microorganisms. Biosurfactants are amphiphilic compounds cause surface tension reduction both aqueous solutions and hydrocarbon mixtures. The main purpose of this work was to characterize biosurfactant produced by Lactobacillus strains.  Identification using 16s rDNA identified the isolates as L. acidophilus for Fm1 and L. pentosus for Y1. Effect different parameters (temperature, PH and Salinity) were studied to evaluate the stability of biosurfactant after treatment.  In addition, critical micelle concentration of biosurfactant, emulsification index and viscosity reduction of palm and engine oils have been studied. The results revealed that, the biosurfactant from L. acidophilus and L. pentosus maintains its emulsifications activities unaffected in the wide range of parameter's study except slightly decreasing in emulsification index values at salinity 15%. The maximum reduction in surface tension was 18.05 mN/m with minimum concentration of critical micelle concentration of 7.5 mg/ml and high decrease of palm and engine oil viscosity of 110.1 and 165.3% respectively. This study concluded that, the emulsification activity, the surface activity and the stability to heat treatment, different PH and salinity of biosurfactant of Lactobacillus strains revealed the application of the biosurfactant in food, pharmaceutical, cosmetics industries and oil recovery.