For cells of Brevibacterium sp. under conditions of biotin limitation, the efflux of metabolites through the cell membrane was affected by temperature. After the temperature shift-up from 30degreesC to 38degreesC, both the specific production rate of glutamic acid and the excretion of intracellular materials, such as glucose-6-phosphate and nucleotides, were increased simultaneously. For the production of glutamic acid, not only the yield but also the specific production rate was increased by the temperature shift-up.