La biosynthèse des acides aminés à chaîne branchée et des purines : deux voies essentielles pour une croissance optimale de Streptococcus thermophilus dans le lait

摘要: Branched-chain amino acids and purine biosynthesis: two pathways essential for optimal growth of Streptococcus thermophilus in milk. Slowing down delays thermophilusgrowth milk have negative effects dairy technology. Our objectives are to under- stand the reasons those delays, identify some functions S. thermophilusin To reach this goal, a random insertional mutagenesis was performed on strain chosen its ability grow rapidly We obtained 14 different mutants, affected their capacity quickly Four them were further character- ized: mutated branched-chain biosynthesis operon others nucleotides operon. Consequently, functional thermophilus. results suggested that amount both nucleotides, present milk, directly consumable is not sufficient an growth. Moreover, we identified as / branched chain acid