The dynamics of an Streptomyces coelicolor A3(2) culture in a 20-1 computer-controlled batch bioreactor was investigated both experimentally and theoretically. In defined medium, depending on the initial conditions, the calculated value of some of the kinetic parameters were : maximum specific growth rate, 0.03 h(-1) death rate constant. 1.4-6.3 x 10(-3) h(-1); observed biomass yield, 0.21 g cells g(-1) glucose and the maintenance coefficient for the cells, 0.0448 g glucose g(-1) cells h(-1). According to both experimental observations and the Luedeking-Piret model, actinorhodin production was found to be growth-associated, This paper provides the first published quantitative information on the main kinetic parameters describing the activity of S. coelicolor in batch culture.