Technologically important properties of lactic acid bacteria isolated from raw milk of three breeds of Algerian dromedary (Camelus dromedarius)

A total of 9 samples of individual dromedary raw milks from N’ajjer (3), Targui (3) and Reguibi (3) breeds were collected from 3 camels nomad herd in south Algeria and were analysed for bacterial load. A totalof 23 strains of lactic acid bacteria were isolated, out of which 12 strains were cocci and 11 strains were facultatively heterofermentative lactobacilli. Lactic acid bacteria were identified on the basis ofphenotypic characters as Lactococcus lactis subsp. lactis, Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum andLactobacillus rhamnosus. Whole cells of lactococci, enterococci and lactobacilli showed proteolytic activity and were found to differed in terms of their acidifying activities. Proteolytic and autolyticactivity were generally higher for most lactobacilli compared to other isolates and none of the strains produced biogenic amines in the method applied. A wide variety of this 23 lactic acid bacteria strainsisolated from Algerian dromedary milks that showed potentially important properties suggest that they are good candidate for camels milk processing or other dairy fermentation process

Bacteriocinogenic potential and genotypic characterization of three Enterococcus faecium isolates from Algerian raw milk and traditional butter

The detection of bacteriocinogenic potential of Enterococcus sp. isolates from Algerian raw milk coded LO4 and LO12 and from traditional butter coded BRO2 was carried on M17 buffered medium. PCR amplification of Enterococcus sp. DNA using specific enterococcal primers gave 733 bp fragments. The phylogenetic analysis using the neighbour joining method further supported the identification of the three strains as Enterococcus faecium. These bacteria were bacteriocinogenic against Pseudomonas sp, Proteus mirabilis and E. faecium. Lyophilisate extracts were tested for sensitivity to enzymes, heating and effect of pH. Complete inactivation in bacteriocinogenic activity was observed after treatment with proteolytic enzymes. The antibacterial activity from E faecium LO12 was stable (1280 AU/ml) for range pH 2 to 12. Maximal activity from BRO2 strain was at pH 7 (20480 AU/ml) and from LO4 strain was at pH 7 and 6 (2560 AU/ml). Antibacterial activities of E. faecium BRO2 (5120 AU/ml) and E. faecium LO12 (640 AU/ml) remained stable at 60°C for 30 min. The antibacterial activity of .E faecium LO4 was stable at 100°C for 30 min (5120 AU/ml)

Lactic acid bacteria isolated from fermented green olives produced in Western Algeria

Vingt trois isolats de bactéries lactiques ont été isolés à partir de 10 échantillons d’olives vertes fermentées dans l’ouest algérien. Elles ont été caractérisées et identifiées sur la base de l’observation microscopique, des propriétés biochimiques et la capacité de fermentation des sucres. Onze souches étaient identifiées à l’espèce Lactobacillus plantarum, 7 à l’espèce Enterococcus faecium et 5 à l’espèce Lactococcus lactis ssp. lactis. Cette étude préliminaire a pour objectif l’élaborationd’une collection locale de culture bactériènnes starters

Identification of lactic acid bacteria isolated from milk and fermented olive oil in western Algeria

Un total de 154 souches de Lactococcus, Lactobacillus, Enterococcus ou Streptococcus ont été isolées à partir d’échantillons d’huile d’olive ou d’échantillons de laits crus de vache, de chèvre et de brebis collectés dans l’ouest algérien. Les tests de caractérisation morphologiques et biochimiques ont permis d’identifier 50 souches de Lc. lactis subsp. lactis, 34 souches de Lc. lactis subsp. biovar. diacetylactis et 35 souches de Lc. lactis subsp. cremoris. Vingt et une souches ont été identifiées comme étant des Lactobacillus sp., 11 souches des Enterococcus faecium et 03 souches des Streptococcus bovis

Statistical optimization of lactic acid production by Lactococcus lactis strain, using the central composite experimental design

The individual and interactive effects of a total inoculums size (% v/v), fermentation temperature and skim milk dry matter added (% w/v) on the lactic acid production by Lactococcus lactis LCL strain were studied by quadratic response surface methodology. The central composite design (CCD) was employed to determine maximum lactic acid production at optimum values for process variables and a satisfactory fit model was realized. The mathematical relationship of the lactic acid production on the three significant independent variables can be approximated by a nonlinear polynomial model. Predicted values were found to be in a good agreement with experimental values (R2 of 96.7% and R2(adj) of 92.1% for response Y). The result of optimization predicted by the model has shown that the maximal result for lactic acid production revolved around 92°D at the optimal condition with 2% of inoculums size, temperature at 30°C and skim milk dry matter added at a central point of 2% (w/v).Keywords: Central composite design, Lactococcus lactis, lactic acid production, inoculum size, temperature, skim milk dry matter.African Journal of Biotechnology, Vol 13(45) 4259-426