Global Advanced Research Journal of Agricultural Science (GARJAS) ISSN: 2315-5094
December 2014 Special Anniversary Review 2014 Vol. 3(12): pp. 423-432
Copyright © 2014 Global Advanced Research Journals
Full Length Research Paper
Characterization of a new isolate of Lactobacillus brevis WD19 from Algerian goat milk with proteolytic activity
W. Dib1, V. Biscola2, Y. Choiset3, J-M. Chobert3, T. Haertlé3, A. Chekroun1, D. Saidi1, O. Kheroua1.
1Laboratory of Physiology of Nutrition and Food Safety, Department of Biology, Faculty of Science of Nature and Life, University of Oran 31000, Algeria.
2Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo. São Paulo, SP - Brazil.
3UR 1268, Biopolymères Interactions Assemblages, INRA, F-44300 Nantes, France.
*Corresponding Author’s Email: email@example.com;
Tel /Fax: 00213 775 147 581/00213 41 581 925.
Accepted 04 December, 2014
A collection of 60 isolates was obtained from 15 samples of Algerian goat milk. Five isolates (2 cocci and 3 bacilli) were able to hydrolyze milk proteins in UHT skim milk, but to different extents. The highest proteolytic isolate was selected and identified as Lactobacillus brevis by 16S rDNA sequencing (it was, therefore, named Lactobacillus brevis WD19). Experiments regarding bacterial growth, pH reduction capability and lactic acid production of LB19 were carried out by milk fermentation at 45 oC for 24 h. A significant increase in lactic acid production (p <0.001) was observed for fermented milk samples (51.6 ± 1.4 o D), followed by a pH decrease (5.11 ± 0.4) and a significant increase in bacterial numbers (5.1010 UFC/mL), which corresponded to high number of functions α-NH2 (90.78 ± 9.62 µM/mg), when compared to the results observed for controls (19.4 ± 0.4 ° D, pH 6.68 ± 0.1, 8.24 ± 0.39 µM/mg). The characterization of proteolytic activity of the selected strain, performed using Na-caseinate and whey proteins in non-proliferative cell system, revealed that the optimum conditions for the proteolysis were achieved at 37-45 ºC and pH 7.2. The tests performed with protease inhibitors demonstrated that L. brevis WD19 produces both serine and metalloproteinases. The results presented in this manuscript suggest that L. brevis WD19 could be used in the manufacture of hypoallergenic fermented dairy products.
Keywords: Lactobacillus brevis, proteolytic activity, goat milk, fermented milk.
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- Y. Choiset on Google Scholar
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- T. Haertlé on Google Scholar
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