... at pH 7 and 37 C. CO2 production rate (CTR) was used for on-line regulation of the acetate fe... more ... at pH 7 and 37 C. CO2 production rate (CTR) was used for on-line regulation of the acetate feedrate. ... Therefore, the correlation between acetate consumption rate (ACR) and CO2 productionrate (CTR) was a matter of detailed analysis to enable an optimal on-line process ...
REF. Laccase-Catalyzed L-DOPA Oxidation on Macro and Microreactor Scale. Marina Tima a,b , Bruno... more REF. Laccase-Catalyzed L-DOPA Oxidation on Macro and Microreactor Scale. Marina Tima a,b , Bruno Zelić b , Đurđa Vasić-Rački b , Polona nidarič-Plazl c and Igor Plazl c *. a: Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia. ...
Using the pyruvate production strain Escherichia coli YYC202 ldhA::Kan different process alternat... more Using the pyruvate production strain Escherichia coli YYC202 ldhA::Kan different process alternatives are studied with the aim of preventing potential product inhibition by appropriate product separation. This strain is completely blocked in its ability to convert pyruvate into acetyl-CoA or acetate, resulting in acetate auxotrophy during growth in glucose minimal medium. Continuous experiments with cell retention, repetitive fed-batch, and an in situ product recovery (ISPR) process with fully integrated electrodialysis were tested. Although the continuous approach achieved a high volumetric productivity (Q P ) of 110 g L À1 d À1 , this approach was not pursued because of long-term production strain instabilities. The highest pyruvate/glucose molar yield of up to 1.78 mol mol À1 together with high Q P 145 g L À1 d À1 and high pyruvate titers was achieved by the repetitive fed-batch approach. To separate pyruvate from fermentation broth a fully integrated continuous process was developed. In this process electrodialysis was used as a separation unit. Under optimum conditions a (calculated) final pyruvate titer of >900 mmol L À1 (79 g L À1 ) was achieved. B 2004 Wiley Periodicals, Inc.
A family of 10 competing, unstructured models has been developed to model cell growth, substrate ... more A family of 10 competing, unstructured models has been developed to model cell growth, substrate consumption, and product formation of the pyruvate producing strain Escherichia coli YYC202 ldhA::Kan strain used in fed-batch processes. The strain is completely blocked in its ability to convert pyruvate into acetyl-CoA or acetate (using glucose as the carbon source) resulting in an acetate auxotrophy during growth in glucose minimal medium. Parameter estimation was carried out using data from fed-batch fermentation performed at constant glucose feed rates of q(VG)=10 mL h(-1). Acetate was fed according to the previously developed feeding strategy. While the model identification was realized by least-square fit, the model discrimination was based on the model selection criterion (MSC). The validation of model parameters was performed applying data from two different fed-batch experiments with glucose feed rate q(VG)=20 and 30 mL h(-1), respectively. Consequently, the most suitable model was identified that reflected the pyruvate and biomass curves adequately by considering a pyruvate inhibited growth (Jerusalimsky approach) and pyruvate inhibited product formation (described by modified Luedeking-Piret/Levenspiel term).
A simple unstructured mathematical model for the oxidation of glucose to 2,5-diketo-D-gluconic ac... more A simple unstructured mathematical model for the oxidation of glucose to 2,5-diketo-D-gluconic acid with Erwinia citreus was developed. The kinetic parameters of the model were estimated by the oxygen partial pressure method and directly from the temporal response obtained from the experimental data collected in the batch fermentation. The simple developed model based on the kinetic measurements was able to simulate quite well the dynamic behaviour of the batch fermentation.
... at pH 7 and 37 C. CO2 production rate (CTR) was used for on-line regulation of the acetate fe... more ... at pH 7 and 37 C. CO2 production rate (CTR) was used for on-line regulation of the acetate feedrate. ... Therefore, the correlation between acetate consumption rate (ACR) and CO2 productionrate (CTR) was a matter of detailed analysis to enable an optimal on-line process ...
REF. Laccase-Catalyzed L-DOPA Oxidation on Macro and Microreactor Scale. Marina Tima a,b , Bruno... more REF. Laccase-Catalyzed L-DOPA Oxidation on Macro and Microreactor Scale. Marina Tima a,b , Bruno Zelić b , Đurđa Vasić-Rački b , Polona nidarič-Plazl c and Igor Plazl c *. a: Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia. ...
Using the pyruvate production strain Escherichia coli YYC202 ldhA::Kan different process alternat... more Using the pyruvate production strain Escherichia coli YYC202 ldhA::Kan different process alternatives are studied with the aim of preventing potential product inhibition by appropriate product separation. This strain is completely blocked in its ability to convert pyruvate into acetyl-CoA or acetate, resulting in acetate auxotrophy during growth in glucose minimal medium. Continuous experiments with cell retention, repetitive fed-batch, and an in situ product recovery (ISPR) process with fully integrated electrodialysis were tested. Although the continuous approach achieved a high volumetric productivity (Q P ) of 110 g L À1 d À1 , this approach was not pursued because of long-term production strain instabilities. The highest pyruvate/glucose molar yield of up to 1.78 mol mol À1 together with high Q P 145 g L À1 d À1 and high pyruvate titers was achieved by the repetitive fed-batch approach. To separate pyruvate from fermentation broth a fully integrated continuous process was developed. In this process electrodialysis was used as a separation unit. Under optimum conditions a (calculated) final pyruvate titer of >900 mmol L À1 (79 g L À1 ) was achieved. B 2004 Wiley Periodicals, Inc.
A family of 10 competing, unstructured models has been developed to model cell growth, substrate ... more A family of 10 competing, unstructured models has been developed to model cell growth, substrate consumption, and product formation of the pyruvate producing strain Escherichia coli YYC202 ldhA::Kan strain used in fed-batch processes. The strain is completely blocked in its ability to convert pyruvate into acetyl-CoA or acetate (using glucose as the carbon source) resulting in an acetate auxotrophy during growth in glucose minimal medium. Parameter estimation was carried out using data from fed-batch fermentation performed at constant glucose feed rates of q(VG)=10 mL h(-1). Acetate was fed according to the previously developed feeding strategy. While the model identification was realized by least-square fit, the model discrimination was based on the model selection criterion (MSC). The validation of model parameters was performed applying data from two different fed-batch experiments with glucose feed rate q(VG)=20 and 30 mL h(-1), respectively. Consequently, the most suitable model was identified that reflected the pyruvate and biomass curves adequately by considering a pyruvate inhibited growth (Jerusalimsky approach) and pyruvate inhibited product formation (described by modified Luedeking-Piret/Levenspiel term).
A simple unstructured mathematical model for the oxidation of glucose to 2,5-diketo-D-gluconic ac... more A simple unstructured mathematical model for the oxidation of glucose to 2,5-diketo-D-gluconic acid with Erwinia citreus was developed. The kinetic parameters of the model were estimated by the oxygen partial pressure method and directly from the temporal response obtained from the experimental data collected in the batch fermentation. The simple developed model based on the kinetic measurements was able to simulate quite well the dynamic behaviour of the batch fermentation.
Uploads
Papers by B. Zelić