Comparison of proteolytic activities in various lactobacilli

Abstract

SUMMARYA total of 169Lactobacillusstrains from 12 species (Lb. acidophilus, Lb. brevis, Lb. buchneri, Lb. casei, Lb. delbrueckiisubsp.bulgaricus, Lb. delbrueckiisubsp.delbrueckii, Lb. delbrueckiisubsp.lactis, Lb. fermentum, Lb. helveticus, Lb. paracasei subsp. paracasei, Lb. plantarum and Lb. rhamnosus), isolated from raw milk and various milk products, and 9Lactococcus lactisstrains were evaluated for peptidase activities with five chromogenic substrates and a tryptic digest of casein. Within each species, the peptidase activity of the cell-free extracts of the strains varied. Furthermore, differences were observed between theLactobacilhisspecies andLc. lactis. Lb. helveticushad by far the highest hydrolysing activities towards all substrates, indicating the presence of powerful aminopeptidases, X-prolyl-dipeptidyl aminopeptidases and proline iminopeptidases.Lb. delbrueckiisubsp.bulgaricuspossessed high hydrolysing activities towards substrates containing proline, alanylprolyl–p–nitroanilide and prolyl–p–nitroanilide. On the other hand,Lb. fermentumandLb. breviscould be considered as weakly proteolytic species. A more detailed study with highly proteolyticLactobacillusstrains indicated that at least three different proteinases or endopeptidases were present. Compared withLc. lactis, theLactobacillusstrains had a much lower hydrolytic action on glutamyl-glutamic acid, suggesting that glutamyl aminopeptidase was absent in lactobacilli.

Combined effects of replacement of sucrose with d-tagatose and addition of different probiotic strains on quality characteristics of chocolate milk

“…Afterward, L. casei, L. rhamnosus, and B. lactis were placed, respectively. L. acidophilus and L. casei have high proteolytic activities (Sasaki et al 1995) that improve their acidification rate. Proteolytic activities of probiotics are directly proportional to their acidification rate (Azcarate-Peril et al 2005).…”

Propionibacteria and facultatively heterofermentative lactobacilli weakly contribute to secondary proteolysis of Emmental cheese

“…Cells counts on FH medium did not decrease during incubation, but it could hide a viability decrease of some strains among the population, as already observed in cheese [8]. FHL possess high autolytic activity [3,12] and peptidase activity [33,38]. The raw milk flora of Swiss-type cheese, composed of FHL and PAB has been shown to generally increase proteolysis indexes during ripening, i.e.…”

“…delbrueckii and ssp. lactis [33]. Lysis of L. casei and L. plantarum has not yet been extensively studied but was close to L. helveticus under conditions prevailing in cheese [12].…”

Influence of starter cultures on the proteolysis of Teleme cheese made from different types of milk

“…The overall proteolytic activity of lactobacilli has been found to be higher than that of Lc. lactis because lactobacilli possess additional peptidases and because their peptidases have higher expression levels [21,38]. Also, Str.…”

“…They concluded that, perhaps, the effects of lactobacilli are not the same in cow's milk cheese as in ewe's milk cheese. Sasaki et al [38] found that strains of Lb. paracasei ssp.…”