The growth rate, glucose consumption rate, and production rate of an L-lysine producing Corynebacterium glutamicum mutant were studied in batch and fed-batch cultures. In batch fermentation, higher L-lysine productivity (1.93 g l - 1 h - 1 ) and L-lysine yield of 0.70 g g - 1 were obtained with lower lysine excretion (34 g l - 1 ). A strong enhancement of L-lysine production (110.6 g l - 1 ) was obtained in fed-batch culture, whereas the kinetic parameters remained lower than those observed in batch cultures. In both culture techniques high L-lysine productivity and L-lysine yield occurred at the lower growth rate ranging from 0.02 h - 1 . Enzymatic analysis revealed that the higher L-lysine production could be obtained under a higher phosphoenolpyruvate carboxylase/citrate synthase enzyme activity ratio to avoid biomass production at the expense of L-lysine. This is a direct proof of the important role of both phosphoenolpyruvate carboxylase activity and the composition of the growth medium on the L-lysine overproduction phase.