Enzymatic and functional properties of Lactic Acid Bacteria isolated from Algerian fermented milk products (original) (raw)

Abstract- In the present study, a total of 108 of lactic acid bacteria (LAB) was isolated from Algerian traditional fermented dairy products (Jben, Klila, Raib and Lben) in order to evaluate their enzymatic activities (Proteolytic, α-amylase production, caseinolytic, lipolytic) and antimicrobial proprieties. Twelve representative isolates were selected and characterized with regard to their functional properties. The retained strains were identified using phenotypic and 16S rDNA gene analysis as; Lactococcus lactis subsp lactis (3 strains), L. lactis subsp. cremoris (1 strain), L. lactis subsp. lactis biovar. diacetylactis (2 strains), Lactobacillus plantarum (3 strains), Lactobacillus casei subsp. casei (2 strains) and Leuconostoc mesenteroides (1 strain). Lactococcus strains showed the greatest degree of acidifying and proteolytic activity. However, tow strains of Lactobacillus casei subsp. casei exhibited maximum caseinolytic activity. Furthermore, low lipolytic and amylolytic capacities were detected. The enzymatic potential evaluated with API ZYM system showed that all strains exhibited high Leucine arylamidase, Valine arylamidase and β-Galactosidase activities. Selected LAB were also tested for their antimicrobial activity against Listeria monocytogenes ATCC 7644 using agar well diffusion technique. All extracts of isolates were found to be fully inactivated by proteolytic enzymes, heat stable up to 100°C for 20 min and displayed inhibitory activity at pH from 3.0 to 10.0. Lactic acid bacteria isolated in this study play complex role in the traditional fermentation milk by their functional properties related to a specific enzyme spectrum, acidifying capacity, antimicrobial activities and probiotic properties.