Branched-chain amino acid biosynthesis is essential for optimal growth of Streptococcus thermophilus in milk.

ABSTRACT: Lactic acid bacteria are nutritionally demanding bacteria which need, among other things, amino acids for optimal growth. We identified the branched-chain amino acid (BCAA) biosynthesis pathway as an essential pathway for optimal growth of Streptococcus thermophilus in milk. Through random insertional mutagenesis, we isolated and characterized two mutants for which growth in milk is affected as a consequence of ilvB and ilvC gene interruptions. This situation demonstrates that the BCAA biosynthesis pathway is active in S. thermophilus. BCAA biosynthesis is necessary but not sufficient for optimal growth of S. thermophilus and is subject to retro-inhibition processes. The specificity of the BCAA biosynthesis pathway in S. thermophilus lies in the independent transcription of the ilvC gene e

SUBMITTER: Garault P 

PROVIDER: S-EPMC92433 | biostudies-literature | 2000 Dec

REPOSITORIES: biostudies-literature