Proteolytic, lipolytic and autolytic activities of enterococci strains isolated from Egyptian dairy products

Abstract

-Enterococci were isolated from Egyptian Domiatti and Mish cheeses made from raw milk. The proteolytic, lipolytic and autolytic activities of the isolated strains were studied to select the most appropriate cultures to be used for the enhancement of the organoleptic properties of cheese. The intracellular peptide hydrolase activities of enterococci strains were determined using various synthetic aminopeptidase and dipeptidyl-aminopeptidase substrates. 4-nitrophenyl and 2-nitrophenyl derivatives of fatty acids were used to measure the esterolytic activity of the different strains while emulsions of various triglycerides and butter fat were used to evaluate their lipolytic activities.The autolytic properties of the cultures were also considered. Three strains of Enterococcus faecium were freeze-shocked and evaluated as adjunct cultures in a cheese slurry system. All the strains exhibited an aminopeptidase activity hydrolysing leucyl 4-nitroanilide faster than the arginyl, alanyl, prolyl or glycyl derivatives. An active dipeptidyl-aminopeptidase activity was also detected. The Enterococcus faecium strains showed an active esterase system. The 4-nitrophenyl derivatives of the fatty acids were hydrolysed faster than the 2-nitrophenyl. The lipase substrates were hydrolysed according to the following order: tributyrin > tricaproin > tricaprylin > butterfat. The autolytic properties varied according to the strains tested. Cheese slurries ripened with adjunct Enterococcus faecium exhibited considerably higher levels of water-soluble nitrogen (WSN) and total free amino acids (FAA) when compared to the control after incubation for 5 d at 32 o C. With this finding, a high variability of some technologically relevant properties was found and could be the basis for the selection of specific cultures to be used as adjunct cultures in the production of traditional cheeses. Enterococcus / aminopeptidase / esterase / autolyse / levain atténué

Lipolytic Activity of Lactic Acid Bacteria Isolated from Turkish Pastırma

“…Considering the studies in the literature, it is possible to say that there are many researches about lipolytic enzyme production ability of enterococci species. Lipolytic activity is frequently detected among enterococci [25][26][27]. In our study, E. faecium-97, E. faecium-299, E. faecium-168 and E. faecium-169 showed medium activity.…”

“…In our study, E. faecium-97, E. faecium-299, E. faecium-168 and E. faecium-169 showed medium activity. El-Din et al [27] reported lipolytic Enterococcus strains isolated from some dairy product types using different natural or synthetic substrates, including tributyrin. Simonova et al [1] described lipolytic enterococci isolated from meat products (sausage).…”

Bacterial composition and function during fermentation of Mongolia koumiss

“…In addition, Enterococcus was negatively correlated with protein. Wessels et al (Wessels et al, 1990) and Bassem et al (Bassem et al, 2002) also suggested that Enterococcus produced proteolytic enzymes involved in casein degradation. Overall, LAB played a major role in the fermentation of koumiss.…”

Lipolytic Activity of Potential Probiotic Enterococci and Additive Staphylococci

“…The detection of lipolytic activity among enterococci of dairy and meat (sausage) origin is more common and measured in higher values. El-Din et al (2002) also described lipolytic enterococci isolated from dairy products using several natural and synthetic substrates, including tributyrin; enterococcal lipases hydrolysed tributyrin more rapidly than other simple triglycerides. On the other hand, measurements of the lipolytic activity of bacteria isolated from dairy and meat products are common and even requested because of the product quality.…”