HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by O'Sullivan, L. Articles by Hill, C. Search for Related Content PubMed PubMed Citation Articles by O'Sullivan, L. Articles by Hill, C.

Elevated Enzyme Release from Lactococcal Starter Cultures on Exposure to the Lantibiotic Lacticin 481, Produced by Lactococcus lactis DPC5552

L. O'Sullivan^*,, S. M. Morgan^*,, R. P. Ross^* and C. Hill^,

^* Dairy Products Research Centre, Teagasc, Moorepark, Fermoy, County Cork, Republic of Ireland
Department of Microbiology and
National Food Biotechnology Centre, University College Cork, Republic of Ireland

Corresponding author:
R. P. Ross; e-mail:
pross{at}moorepark.teagasc.ie.

A Lactococcus lactis subsp. lactis strain (DPC5552), which causes the lysis of other lactococcal cultures, was isolated during a screening of raw milk samples for bacteriocin producers. Purification of the bacteriocin produced revealed that production of the lantibiotic, lacticin 481, was associated with the bacteriolytic capability of the strain. However, unlike bacteriocin-induced lysis observed with bacteriocins such as lacticin 3147 and lactococcins A, B, and M (where the target strain is killed), the DPC5552 supernatant gave rise to a situation whereby the target strain continued to grow (albeit at a lower rate) with simultaneous release of the intracellular enzymes lactate dehydrogenase (LDH) and post-proline dipeptidyl aminopeptidase (Pep X). In parallel experiments, 32 AU/ml of the inhibitory activity from L. lactis DPC5552 resulted in a 10- and 6-fold-higher LDH release after 5 h than that with 32 AU/ml of either lacticin 3147 or lactococcin A, B, and M. Laboratory-scale Cheddar cheese-making trials also demonstrated that lacticin 481-producing cultures induced the release of elevated levels of LDH from the starter L. lactis HP, without severely compromising its acid-producing capabilities. These results indicate that lacticin 481-producing strains may provide improved adjuncts for delivering lactococcal intracellular enzymes into the cheese matrix and, thus, improve cheese quality and flavor.

Abbreviation key: LDH = lactate dehydrogenase, RSM = reconstituted skim milk, Pep X = post proline dipeptidyl aminopeptidase X, OD = optical density, LAB = lactic acid bacteria, TFA = trifluoroacetic acid

Key Words: cheese • lactate dehydrogenase • lacticin 481

This article has been cited by other articles:

				S. Garde, M. Avila, P. Gaya, M. Medina, and M. Nunez Proteolysis of Hispanico cheese manufactured using lacticin 481-producing Lactococcus lactis ssp. lactis INIA 639. J Dairy Sci, March 1, 2006; 89(3): 840 - 849. [Abstract] [Full Text] [PDF]

				L. O'Sullivan, M. P. Ryan, R. P. Ross, and C. Hill Generation of Food-Grade Lactococcal Starters Which Produce the Lantibiotics Lacticin 3147 and Lacticin 481 Appl. Envir. Microbiol., June 1, 2003; 69(6): 3681 - 3685. [Abstract] [Full Text] [PDF]