Etude biotechnologique des bactéries lactiques isolées du lait de chèvre cru

Abstract

Lactic acid bacteria (LAB) are essential in the food industry, playing a key role in fermentation processes to produce a variety of foods. Isolation of lactic strains from a sample of raw goat's milk from the El Rogassa region in the wilaya of El Bayadh yielded 10 Gram-positive and catalase-negative isolates. For isolate identification, we used the following tests: growth test at different temperatures: 22°C, 37°C and 45°C; growth test at different pHs: 5, 6.5 and 9.6; growth test in the presence of 6.5% NaCl; growth test in sherman's milk medium; thermoresistant study; acetoin production test and arginine hydrolase test. These tests enabled us to distinguish four main species: Streptococcus thermophilus, Enterococcus durans, Enterococcus faecalis and Lactococcus lactis. And ending our study with technological tests of the isolates where they show satisfactory results for use in the food industry.