Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8966295 | Biochemical Engineering Journal | 2005 | 6 Pages |
Abstract
Effects of pellet morphology on broth rheology are reported for pelleted submerged cultures of the lovastatin producing filamentous fungus Aspergillus terreus, growing in fluidized bed and stirred tank bioreactors. The pellet diameter and compactness were affected by the agitation intensity of the broth; however, the total biomass productivity was not affected. In fluidized beds and stirred tanks with agitation intensity of up to 300 rpm (impeller tip speed of 1.02 m sâ1), the fungal pellets were stable at diameters of up to about 2300 μm. In more intensely agitated stirred tanks (â¥600 rpm; impeller tip speed of â¥2.03 m sâ1), the stable pellet size was only about â¤900 μm. The biomass concentration and the pellet diameter were the main factors that influenced the flow index and the consistency index of the power-law broths. Because the biomass productivity was the same in all experiments in a given type of reactor and the oxygen concentration was kept at â¼400% of air saturation, the pellet size and morphology were not influenced by oxygen mass transfer effects. Pellets were always dense in the core region and no necrosis of the biomass occurred.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Bioengineering
Authors
E.M. RodrÃguez Porcel, J.L. Casas López, J.A. Sánchez Pérez, J.M. Fernández Sevilla, Y. Chisti,