Glutamic acid uptake in Streptococcus salivarius subsp. thermophilus was energy dependent, the source of energy and adaptation to sugar being important to efficiency of uptake. The disaccharides, lactose and sucrose, stimulated uptake, but cells grown in glucose were more active. Optimum temperature was ˜ 40 °C and pH ˜ 7·0. NaCl was strongly inhibitory to the uptake of glutamic acid although not to that of isoleucine. High specificity existed because only L-aspartic acid was inhibitory.