RHEOLOGICAL BEHAVIOR OF FERMENTATION BROTHS IN ANTIBIOTIC INDUSTRY

An experimental study of rheological behavior of three morphological t ypes of fermentation broths in relation to process conditions was carr ied out in industrial and pilot-plant bioreactors. Three industrially manufactured antibiotic broths were studied: Cephalosporin C (fungal), tylosin (actinomycetic), and apramycin (proactinomycetic), in which t he rheology may cause real problems. A viscometer with coaxial cylinde rs and six-blade impeller was used for rheological measurements. The s hear rates range in which both the instruments give similar results wa s determined. During the experiments rheological and morphological beh avior, pH, activity, biomass concentration, fats, glucose, and nitroge n concentrations were studied.All the broths studied exhibited nonNewt onian behavior, which could be described with Ostvald-de-Waele power-l aw model. It was found that the rheological behavior of the broths dur ing the process is closely related to biomass concentration and morpho logical changes of mycelia, so that viscosity could be used as a param eter for process monitoring and regulation. A set of experiments on ox ygen-transfer improvement in the case of the most viscous tylosin brot hs by water addition was also done.