Premium
Amino acid requirements and peptidase activities of Streptococcus salivarius subsp. thermophilus
Author(s) -
Neviani E.,
Giraffa G.,
Brizzi A.,
Carminati D.
Publication year - 1995
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1995.tb03141.x
Subject(s) - amino acid , aminopeptidase , leucine , biochemistry , streptococcus salivarius , glutamic acid , enzyme , streptococcus thermophilus , biology , chemistry , bacteria , streptococcus , lactobacillus , fermentation , genetics
The aim of this work was to investigate the relationship between amino acid requirements and peptidase enzyme systems in three Streptococcus salivarius subsp. thermophilus strains. A synthetic medium without nitrogen components and a milk (RD milk) without its non‐protein nitrogen fraction were prepared with different mixtures of amino acids. The strains showed different amino acid requirements. Some amino acids proved to be essential, some were required, while others did not affect growth. In the synthetic medium, only leucine and glutamic acid were essential for growth. In RD milk, the amino acid requirements were found to be lower, with only the absence of glutamic acid causing complete inhibition of growth. Relationships between aminopeptidase activities of the strains and their amino acid requirements were observed. Strains with higher amino acid requirements were also found to express a wider range of peptidases.