Evaluation of the Potential of Adjuncts for Flavor Compounds Development and Diversification in Short-Aged Cheddar Cheese.

The non-starter microbiota of Cheddar cheese mostly comprises mesophilic lactobacilli, such as , and . These bacteria are recognized for their potential to improve Cheddar cheese flavor when used as adjunct cultures. In this study, three strains of (DPC2071, DPC4206, and DPC4536) were evaluated for their contribution to the enhancement and diversification of flavor in short-aged Cheddar cheese.

Reduced Binding of the Endolysin LysTP712 to Lactococcus lactis ΔftsH Contributes to Phage Resistance.

Absence of the membrane protease FtsH in Lactococcus lactis hinders release of the bacteriophage TP712. In this work we have analyzed the mechanism responsible for the non-lytic phenotype of L. lactis ΔftsH after phage infection.

A bacteriocin gene cluster able to enhance plasmid maintenance in Lactococcus lactis.

Background: Lactococcus lactis is widely used as a dairy starter and has been extensively studied. Based on the acquired knowledge on its physiology and metabolism, new applications have been envisaged and there is an increasing interest of using L. lactis as a cell factory.

Lack of the host membrane protease FtsH hinders release of the Lactococcus lactis bacteriophage TP712.

The temperate bacteriophage TP712 was unable to plaque on Lactococcus lactis ΔftsH lacking the membrane protease FtsH and complementation in trans restored the WT phenotype. Absence of ftsH did not hinder phage adsorption, phage DNA delivery or activation of the lytic cycle. Thin sections revealed that TP712 virions appeared to be correctly assembled inside the ΔftsH host, but were not released.

Cell Wall-active Bacteriocins and Their Applications Beyond Antibiotic Activity.

Microorganisms synthesize several compounds with antimicrobial activity in order to compete or defend themselves against others and ensure their survival. In this line, the cell wall is a major protective barrier whose integrity is essential for many vital bacterial processes. Probably for this reason, it represents a 'hot spot' as a target for many antibiotics and antimicrobial peptides such as bacteriocins.

The putative lactococcal extracytoplasmic function anti-sigma factor llmg2447 determines resistance to the cell wall-active bacteriocin lcn972.

Lactococcin 972 (Lcn972) is a cell wall-active bacteriocin that inhibits cell wall biosynthesis in Lactococcus lactis. In this work, the transcriptomes of the Lcn972-resistant (Lcn(r)) mutant L. lactis D1 and its parent strain were compared to identify factors involved in Lcn972 resistance.

Isolation of Lactococcus lactis mutants simultaneously resistant to the cell wall-active bacteriocin Lcn972, lysozyme, nisin, and bacteriophage c2.

Lactococcin 972 (Lcn972) is a nonlantibiotic bacteriocin that inhibits cell wall biosynthesis by binding to lipid II. In this work, two mutants resistant to Lcn972, Lactococcus lactis D1 and D1-20, with high (>320 arbitrary units [AU]/ml) and low (80 AU/ml) susceptibilities, respectively, have been isolated. Resistance to Lcn972 did not impose a burden to growth under laboratory conditions, nor did it substantially alter the physicochemical properties of the cell surface.

The Lcn972 bacteriocin-encoding plasmid pBL1 impairs cellobiose metabolism in Lactococcus lactis.

pBL1 is a Lactococcus lactis theta-replicating 10.9-kbp plasmid that encodes the synthetic machinery of the bacteriocin Lcn972. In this work, the transcriptomes of exponentially growing L.

Bacteriocins produced by wild Lactococcus lactis strains isolated from traditional, starter-free cheeses made of raw milk.

Sixty bacterial strains were encountered by random amplification of polymorphic DNA (RAPD) and repetitive extragenic palindromic (REP) typing in a series of 306 Lactococcus lactis isolates collected during the manufacturing and ripening stages of five traditional, starter-free cheeses made from raw milk. Among the 60 strains, 17 were shown to produce bacteriocin-like compounds in both solid and liquid media. At a genotypic level, 16 of the strains were identified by molecular methods as belonging to L.

Contribution of the CesR-regulated genes llmg0169 and llmg2164-2163 to Lactococcus lactis fitness.

Lactococcus lactis is one of the main components of the starter cultures used in cheese manufacture. As starter, L. lactis must tolerate harsh conditions encountered either during their production in bulk quantities or during dairy products processing.