Autolytic behaviour of Lactococcus lactis subsp. cremoris and L. lactis subsp. lactis wild isolates from ewes' raw milk cheeses
The peptidoglycan hydrolytic activity and the autolytic properties of 12 Lactococcus lactis subsp. cremoris and 44 L. lactis subsp. lactis wild isolates from ewes' raw milk cheeses were investigated. Peptidoglycan hydrolytic activity against Micrococcus lysodeikticus cells was detected in all lactococcal isolates. A high variability in the autolytic behaviour of L. lactis isolates in 100 mM sodium phosphate buffer was observed, L. lactis subsp. cremoris isolates being generally more autolytic than L. lactis subsp. lactis isolates. Average values of autolysis for L. lactis subsp. cremoris isolates after incubation for 48 h at 30°C were 31.5% for the decrease in optical density at 600 nm, 28.2% for the release of protein, 11.6% for the release of actate dehydregenase activity, and 5.0% for the release of aminopeptidase activity. The respective average values for L. lactis subsp. lactis isolates were 27.1%, 25.5%, 3.1%, and 0.85%. Released lactate dehydrogenase and aminopeptidase activities were only detected in 15 and 4 wild isolates, respectively.
| Main Authors: | , , , |
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| Format: | journal article biblioteca |
| Language: | eng |
| Published: |
2002
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| Online Access: | http://hdl.handle.net/20.500.12792/1672 |
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