Biomedical subjects

C Barrena-Gonzalez

Publications and source records attributed to C Barrena-Gonzalez.

2 recordsLinked to original sources

PubMed1996

Comparative effectiveness of nisin and bacteriocin J46 at different pH values.

A comparative study of the inhibitory activity of nisin, the well-known lantibiotic produced by certain strains of Lactococcus lactis subsp. lactis, and of the bacteriocin produced by L. lactis subsp. cremoris J46, a strain previously isolated from fermented milk, was conducted. For both bacteriocins, the activity against L. lactis subsp. cremoris decreased with increasing pH. In addition, the bacteriocin preparations were more stable at 4 degrees than at 20 degrees C. The influence of the storage temperature was more crucial for nisin. Essentially the same activity was observed for bacteriocin J46 stored for 3 h at 4 degrees or 20 degrees C. More interesting was the observed stability of bacteriocin J46 at pH values between 5.8 and 6.8. For example, about 23% of nisin activity was lost at pH 6.4 whereas no loss of bacteriocin J46 activity was observed.

Bacteriocins↗

PubMed1996

Tween 80 effect on bacteriocin synthesis by Lactococcus lactis subsp. cremoris J46.

Sorbitan polyoxyethylene monooleate (Tween 80) suppressed bacteriocin cell adhesion. Within the range 0-1% (v/v), there was an increase in bacteriocin production in regulated (pH 5.5 or 6.0) batch cultures with increasing Tween 80 concentration. For example, at pH 5.5 and in the presence of 1% Tween 80, bacteriocin production was about fourfold higher than in its absence. However, further increase in Tween 80 concentration did not result in a significant modification of the bacteriocin titre. It was shown that the increase was not linked to an activating effect of the surfactant on preformed enzyme, to an increase of bacteriocin availability or to a sensitization of the target cell, demonstrating that Tween 80 promoted bacteriocin production.

Bacteriocins↗