Titre :
|
Slow milk coagulating variants of Lactobacillus helveticus
|
Auteurs :
|
M. Fortina ;
P. Rossi ;
D. Mora ;
AL Et
|
Type de document :
|
article/chapitre/communication
|
Année de publication :
|
1996
|
Format :
|
p. 33-38
|
Langues:
|
= Anglais
|
Catégories :
|
INDUSTRIE AGRO-ALIMENTAIRE
|
Mots-clés:
|
LAIT
;
COAGULATION
;
BACTERIE LACTIQUE
;
CULTURE BACTERIENNE
|
Résumé :
|
Curing experiments were performed on Lactobacillus helveticus strain ATCC 15009 in order to find a correlation between the presence of three extrachromosomal elements and specific phenotypic traits. Mitomycin C treatment of the strain was found to result in an appearance of slow-coagulation variants unable to coagulate milk in 24 h at 42 degrees C. The effect of mitomycin C on phenotypic and genotypic characteristics of L. Helveticus was therefore further examined. The presence of mitomycin C appeared to act on the proteolytic system of the strain: slow variants exhibited a poor casein breakdown (50% less) compared with the parental strain. Aminopeptidase activity and lactose utilization were unaffected. The phenotypic variation is possibly due to a point mutation of genetic patrimony.
|
Source :
|
Folia microbiol., vol.41
|