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Instabilities of product formation in a fed‐batch culture of Penicillium chrysogenum
Author(s) -
Hegewald E.,
Wolleschensky B.,
Guthke R.,
Neubert M.,
Knorre W. A.
Publication year - 1981
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260230715
Subject(s) - fermentation , productivity , sucrose , biomass (ecology) , growth rate , chemistry , pulp and paper industry , environmental science , mathematics , food science , agronomy , biology , engineering , geometry , macroeconomics , economics
By investigation of a model of benzylpenicillin fermentation it was demonstrated that high fermentation productivity is connected with low stability. The increasing instability is not the result of external disturbances but of peculiarities inherent to the system. The main process variables and the essential parameters were selected by analysis of data obtained from fermentation runs in a pilot plant. By simulation on an analog computer it was shown that the proposed model gives a sufficient description of the kinetic behavior of the fermentation runs. By varying the initial conditions it was possible to obtain two types of fermentation runs. One type is distinguished by a high productivity connected with low initial concentrations of sucrose. An increase of the initial sucrose concentration also causes an increase of productivity. When a certain value of this concentration is exceeded a changeover to a faster growth of biomass takes place combined with the breakdown of productivity. The same phenomenon occurs at a defined initial concentration of sucrose if a disturbance of oxygen transfer rate takes place. Whether the culture stays in the one or in the other state after the disturbance has passed depends on the duration, the strength, and the beginning of the disturbance. In the pilot plant similar behavior can be observed. The sensitivity of fermentation processes to disturbances increases with the increase of productivity.