Abstract
BACKGROUND
Gluconic acid production by a glucose oxidase (GOx-EC number 1.1.3.4 ) and catalase (CAT – EC number 1.11.1.6) system has been proposed. However, the bioprocess optimal design and operation are limited by the lack of kinetic models of GOx involving oxygen as substrate. Herein, the GOx-CAT system is modeled considering a continuous oxygen supply at a bioreactor lab scale. Initially, experiments and modeling for parameter estimation of KLa and the individual enzymes were conducted. Then, experiments and modeling for the GOx-CAT system were performed for final model tuning. Additionally, the model quality is evaluated, which allows a deeper understanding of the system phenomenology.
RESULTSFrom the oxygen transport model tuning, a highly accurate KLa estimation was obtained (R2>0.98 and confidence interval <2%). The highest oxygen transport rate was obtained for the combined system Buffer-antifoam-GOx-CAT, being 2.5 times larger than obtained for DI water. Kinetic models for the individual enzymes were very accurate and the parameters were fully identifiable. For the integrated system, the gluconic acid evolution is properly predicted and there is a loss of predictive power for the oxygen model. Parameter identifiability analysis shows that KcatCAT and KMHPCAT interpretability is compromised. However, the sensitivity analysis indicates the model must not be simplified.
CONCLUSIONS
Herein we have demonstrated that is a complex parameter to estimate multi-enzymatic systems, due to its dependency on medium composition, particularly with GOx. Still, based on the acceptable model predictive power, the calculated parameters could be used for studies on the process design phase.
Gluconic acid production by a glucose oxidase (GOx-EC number 1.1.3.4 ) and catalase (CAT – EC number 1.11.1.6) system has been proposed. However, the bioprocess optimal design and operation are limited by the lack of kinetic models of GOx involving oxygen as substrate. Herein, the GOx-CAT system is modeled considering a continuous oxygen supply at a bioreactor lab scale. Initially, experiments and modeling for parameter estimation of KLa and the individual enzymes were conducted. Then, experiments and modeling for the GOx-CAT system were performed for final model tuning. Additionally, the model quality is evaluated, which allows a deeper understanding of the system phenomenology.
RESULTSFrom the oxygen transport model tuning, a highly accurate KLa estimation was obtained (R2>0.98 and confidence interval <2%). The highest oxygen transport rate was obtained for the combined system Buffer-antifoam-GOx-CAT, being 2.5 times larger than obtained for DI water. Kinetic models for the individual enzymes were very accurate and the parameters were fully identifiable. For the integrated system, the gluconic acid evolution is properly predicted and there is a loss of predictive power for the oxygen model. Parameter identifiability analysis shows that KcatCAT and KMHPCAT interpretability is compromised. However, the sensitivity analysis indicates the model must not be simplified.
CONCLUSIONS
Herein we have demonstrated that is a complex parameter to estimate multi-enzymatic systems, due to its dependency on medium composition, particularly with GOx. Still, based on the acceptable model predictive power, the calculated parameters could be used for studies on the process design phase.
| Original language | English |
|---|---|
| Journal | Journal of Chemical Technology and Biotechnology |
| Volume | 98 |
| Issue number | 6 |
| Pages (from-to) | 1520-1531 |
| ISSN | 0268-2575 |
| DOIs | |
| Publication status | Published - 2023 |
Keywords
- Gluconic acid
- GOx‐CAT kinetic parameters
- Oxidoreductase
- KLa estimation