Characterization of Lactobacillus species proposed as probiotics

Abstract

An isolated Lactobacillus from several various sources were identified depending on morphological, microscopically and biochemical tests in vitro analysis of probiotic properties that included: an ability to tolerate in different concentration of bile salt, survival in acidic conditions, their antimicrobial activity, and S-layer characterizations were carried out. It was noticed that isolates of Lactobacillus rhamnosus and L. delbrueckii have a broad activity of antimicrobial and found the isolate L. rhamnosus represented with a survival percentage 6.9% at pH 4.5 and 5.1% at pH 2.0) also L. rhamnosus (5.7% at pH 4.5 and 4.9% at pH 2.0) tolerated acidic media, Lactobacillus spp. has antimicrobial activity against all gram-positive and negative tested isolates. 70 kDa of S-layer protein bands were detected with whole-cell SDS-PAGE analysis, and it's predominant in cells of isolates which grown in MRS broth anaerobically. It was noticed that the collected Lactobacillus isolates could be used as probiotic.

Keywords

• lactobacillus spp.
• acidic tolerance
• bile tolerance
• s-layer