Full Length Research Paper

Phenotypic characterization of Lactobacillus strains isolated from different biotopes

Messaouda Boukhemis¹, Baida Djeghri-Hocine¹, Ali Tahar¹ and Abdeltif Amrane²*

¹Département de biochimie, Université Badji-Mokhtar, BP 12, 23000 Annaba, Algeria.

²UMR CNRS 6226 ‘Sciences Chimiques de Rennes’ Equipe Chimie et Ingénierie des Procédés - Université de Rennes 1 / ENSCR, ENSCR, Campus de Beaulieu, Avenue du Général Leclerc, 35708 Rennes Cedex 7, France.

*Corresponding author. E-mail: abdeltif.amrane@univ-rennes1.fr.

Tel.: (+33) 2 23 23 81 55. Fax: (+33) 2 23 23 81 20.

Accepted 6 July, 2009

   Abstract

Thirty three strains of Lactobacillus were isolated from human milk and infant faeces, animal (cow and goat) milks and from plants (Anagalis arvensis and Bromus mango species). The various strains were identified based on phenotypic tests. Amongst them, 12 strains belonged to group 1, which comprised L. acidophilus, L. helveticus and L. delbrueckii ssp. bulgaricus strains; 16 strains belonged to group 2, which comprised L. casei (ssp. casei and ssp. rhamnosus) and L. plantarum strains; and 5 strains belonged to group 3, which comprised L. brevis and L. fermentum. The variance analysis (with one-fixed criterion classification) of the potential for milk coagulation after 6 and 24 h of growth made possible the characterization of two homogeneous groups, fast and low acidifying strains. The human strains showed a resistance to acidic pH and to bile, indicating a tolerance to gastric acid. The probiotic potential was confirmed for one strain, owing to its antagonistic effect on Escherichia coli.

Key words: Lactic acid bacteria, isolation, characterisation, probiotics, statistical analysis.