title: Production of Extracellular Polysaccharide by Zoogloea ramigera.
abstract: In batch cultures of Zoogloea ramigera the maximum rate of exopolysaccharide synthesis occurred in a partly growth-linked process. The exopolysaccharide was attached to the cells as a capsule. The capsules were released from the cell walls after 150 h of cultivation, which caused the fermentation broth to be highly viscous. Ultrasonication could be used to release capsular polysaccharide from the microbial cell walls. Treatment performed after 48 to 66 h of cultivation revealed exopolysaccharide concentration and apparent viscosity values in accordance with values of untreated samples withdrawn after 161 h of cultivation. The yield coefficient of exopolysaccharide on the basis of consumed glucose was in the range of 55 to 60% for batch cultivations with an initial glucose concentration of 25 g liter. An exopolysaccharide concentration of up to 38 g liter could be attained if glucose, nitrogen, and growth factors were fed into the batch culture. The oxygen consumption rate in batch fermentations reached 25 mmol of O(2) liter h during the exopolysaccharide synthesis phase and then decreased to values below 5 mmol of O(2) liter h during the release phase. The fermentation broth showed pseudoplastic flow behavior, and the polysaccharide was not degraded when growth had ceased.
authors.affiliation: Department of Technical Microbiology, Chemical Center, University of Lund, S-220 07 Lund 7, Sweden.
authors.forename: A B
authors.initials: AB
authors.lastname: Norberg
authors.forename: S O
authors.initials: SO
authors.lastname: Enfors