title: Oxygen profiles and structure of Penicillium chrysogenum pellets.
abstract: Oxygen profiles were measured polarographically with micro-needle electrodes in single fixed pellets of Penicillium chrysogenum. The oxygen concentration, the grade of turbulence and the flow conditions of the outer medium were varied. Pellets were then histologically investigated. Under our experimental conditions the pellets were found to contain a 200 micrometers thick active outer zone with intact cells. In this zone, the oxygen partial pressure decreased from the initial values to zero. The results show that the Po2 profile within the pellet is strongly influenced by the Po2 of the outer medium. Apart from molecular diffusion, surface turbulence as well as a convective flow through the pellets are of importance for the oxygen transport.
mesh_terms: D004058:Diffusion; D010101:Oxygen Consumption; D010407:Penicillium / Q000378:metabolism*; D010408:Penicillium chrysogenum / Q000254:growth & development / Q000378:metabolism*