Research Article Oxygen Mass Transfer Rate in a Pressurized

Oxygen mass transfer from air to the liquid phase in bioreactors with aerobic cultures has long been a serious impairment to the productivity of various biopro-cesses. An increase of the oxygen mass transfer rate (OTR) can be the key to over-come oxygen limitation. The influence of higher air pressure on OTR was mea-sured and a significantly enhanced OTR could be obtained. The oxygen volumetric mass transfer coefficient (kLa) was described by a function of the air pressure in a stirred lab-scale pressurized bioreactor. The correlation obtained proved that kLa slightly decreased with higher air pressure, following a power function