The synthesis of heterologous proteins in Lactococcus lactis is strongly influenced by the promoter selected for the expression. The nisin A promoter is commonly used for induced expression of proteins in L. lactis, whereas few constitutive promoters (P45 and the weaker P32) have been used for protein expression studies. In this study, eight different putative strong constitutive promoters were...

Nisin-producing transconjugants were generated by mating nisin-producing strains of Lactococcus lactis subsp. lactis with derivatives of L. lactis subsp. lactis LM0230. The sucrose-utilizing ability and reduced bacteriophage sensitivity were also transferred with the nisin-producing character. Pulsed-field gel electrophoretic analysis of genomic DNA from donor, recipient, and nisin-producing tr...

Lactococcus lactis produced more exopolysaccharide (EPS) on glucose than on fructose as the sugar substrate, although the transcription level of the eps gene cluster was independent of the sugar source. A major difference between cells grown on the two substrates was the capacity to produce sugar nucleotides, the EPS precursors. However, the activities of the enzymes required for the synthesis ...

The present study describes the screening of five lactic acid bacteria (LAB) for use as probiotics based on their competitive adhesion and production of antagonistic substances against some fish pathogens. A reduction of adhesion of all pathogenic strains tested was obtained with three of the LAB strains (Lactococcus lactis subsp. lactis CLFP100, Lactococcus lactis subsp. cremoris CLFP102 and L...

Bacillus subtilis and Lactococcus lactis are ideal hosts for the production of extracellular heterologous proteins of major commercial importance. A recombinant gene for the novel Ganoderma lucidium immunomodulatory protein LZ-8, recombinant LZ-8, was designed encoding the same amino acid sequence but using the preferred codons for both strains and was synthesized by overlapping extension PCR. ...

The Lactococcus lactis pfl gene, encoding pyruvate formate-lyase (PFL), has been cloned and characterized. The deduced amino acid sequence of the L. lactis PFL. protein showed high similarity to those of other bacterial PFL proteins and included the conserved glycine residue involved in posttranslational activation of PFL. The genetic organization of the chromosomal pfl region in L. lactis show...

Measuring the viability of probiotic microorganisms in food products using plate count methodology is a common practice due to the simplicity (ease of performance), inexpensive and routine testing characters ofthis method. In present study, the suitability of de man rogosa and sharpe agar (MRS) bile agar medium forthe selective enumeration of mixed probiotic bacteria (Lactobacillus ...

The pneumococcal serotype 14 polysaccharide was produced in Lactococcus lactis by coexpressing pneumococcal polysaccharide type 14-specific genes (cpsFGHIJKL(14)) with the lactococcal regulatory and priming glucosyltransferase-encoding genes specific for B40 polysaccharide (epsABCD(B40)). The polysaccharide produced by Lactococcus was secreted in the medium, simplifying downstream processing an...