AbstractLiquid‐phase mass transfer coefficient in bioreactors have been examined. A theoretical model based on the surface renewal concept has been devloped. The predicted liquid‐phase mass transfer coefficients are compared with the experimental data for a mycelial fermentation broth (Chaetomium cellulolyticum) and model media (carboxymethyl cellulose) in a bench‐scale bubble column reactor. The liquid‐phase mass transfer coefficient is evaluated by dividing the volumetric mass transfer coefficient obtained experimentally by the specific surface area estimated using the available correlations. The available literature data in bubble column and stirred tank bioreactors is also used to test the validity of the proposed model. A reasonable agreement between the model and the experimental data is found.