Cultivation of bacteria requires high levels of agitation and aeration to satisfy the mass transfer requirements of the cells. Associated with these conditions are turbulent forces which may act on the surfaces of cells and be detrimental to their growth, metabolism and morphology. The kinetics and mechanism of hydrodynamic trauma has been investigated for the breakup of aggregates of Corynebacterium glutamicum (A TCC 13032) in a stirred-tank reactor and a capillary flow loop system. The effect of forces associated with turbulent eddies in the impeller discharge zone of the stirred tank reactor has been compared with that of collapsing air bubbles at the air medium interface. A model is presented to describe the initial rate of aggregate breakup caused by fluid-aggregate interactions. It assumes that aggregate disruption is caused by the interaction of aggregates with similarly sized turbulent eddies. The extent of aggregate breakup is a function of the magnitude of the turbulent force as well as the total duration of the force event. The applicability of the model to animal cell systems has been investigated. Results showed that both the interaction of microbial cells with turbulent eddies in the viscous dissipation subrange in the impeller discharge zone, as well as with collapsing air bubbles at the air medium interface contributed to the total force acting on the cells.