The Experts below are selected from a list of 118476 Experts worldwide ranked by ideXlab platform
B. Kristiansen - One of the best experts on this subject based on the ideXlab platform.
-
Correlation of Aspergillus niger broth rheological properties with Biomass Concentration and the shape of mycelial aggregates
Biotechnology and Bioengineering, 1993Co-Authors: E. S. Olsvik, K.g. Tucker, Colin R. Thomas, B. KristiansenAbstract:Aspergillus niger was grown in a 7-L chemostat at Biomass levels of 7 to 9 gL−1; dilution rates of 0.03, 0.05, 0.075, and 0.009 h−1; and dissolved oxygen tensions of 7%, 12%, and 40% of air saturation. Broth rheological measurements were made on-line, while off-line image analysis was used to measure mycelial morphology, including characterization of mycelial aggregates (clumps). Under all conditions, more than 87% of the hyphase were in clumps, the shape of which determined the rheological characteristics of the broth. In particular, the power law consistency index could be correlated with the Biomass Concentration and the roughness factor of the clumps, which describes their hairiness. A decrease in specific growth rate decreased roughness, possibly due to changes in the amount of clump breakup. However, decreases of roughness with increasing dissolved oxygen tension might rather imply some effect on hyphal–hyphal interactions within the clumps. © 1993 John Wiley & Sons, Inc.
-
Influence of oxygen tension, Biomass Concentration, and specific growth rate on the rheological properties of a filamentous fermentation broth
Biotechnology and bioengineering, 1992Co-Authors: E. S. Olsvik, B. KristiansenAbstract:The influence of oxygen tension, Biomass Concentration, and specific growth rate on the rheological properties of an Aspergillus niger fermentation broth was investigated by growing the fungus in continuous culture. The rheological properties were measured on-line using an impeller rheometer system. The effect of the specific growth rate on broth rheology was strongly influenced by the dissolved oxygen, (DO) Concentration in the broth. At DO Concentrations above 10% of saturation, K increased with the dilution rate, and at DO Concentrations below 10% of saturation, K decreased with increasing dilution rate. The largest influence of a change in the DO Concentration on the viscosity of the broth was found at the lowest growth rates and the lowest DO Concentrations. K/x, a term that gives a simple description of the structure or the morphology of the culture, was found to increase with Biomass Concentration. © 1992 John Wiley & Sons, Inc.
Vytautas Galvanauskas - One of the best experts on this subject based on the ideXlab platform.
-
Generic estimator of Biomass Concentration for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures based on cumulative oxygen consumption rate
Microbial cell factories, 2019Co-Authors: Renaldas Urniezius, Arnas Survyla, Dziugas Paulauskas, Vladas Algirdas Bumelis, Vytautas GalvanauskasAbstract:Background The focus of this study is online estimation of Biomass Concentration in fed-batch cultures. It describes a bioengineering software solution, which is explored for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures. The experimental investigation of both cultures presents experimental validation results since the start of the bioprocess, i.e. since the injection of inoculant solution into bioreactor. In total, four strains were analyzed, and 21 experiments were performed under varying bioprocess conditions, out of which 7 experiments were carried out with dosed substrate feeding. Development of the microorganisms’ culture invariant generic estimator of Biomass Concentration was the main goal of this research.
-
Generic estimator of Biomass Concentration for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures based on cumulative oxygen consumption rate
Microbial Cell Factories, 2019Co-Authors: Renaldas Urniezius, Arnas Survyla, Dziugas Paulauskas, Vladas Algirdas Bumelis, Vytautas GalvanauskasAbstract:Background The focus of this study is online estimation of Biomass Concentration in fed-batch cultures. It describes a bioengineering software solution, which is explored for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures. The experimental investigation of both cultures presents experimental validation results since the start of the bioprocess, i.e. since the injection of inoculant solution into bioreactor. In total, four strains were analyzed, and 21 experiments were performed under varying bioprocess conditions, out of which 7 experiments were carried out with dosed substrate feeding. Development of the microorganisms’ culture invariant generic estimator of Biomass Concentration was the main goal of this research. Results The results show that stoichiometric parameters provide acceptable knowledge on the state of Biomass Concentrations during the whole cultivation process, including the exponential growth phase of both E. coli and S. cerevisiae cultures. The cell culture stoichiometric parameters are estimated by a procedure based on the Luedeking/Piret-model and maximization of entropy. The main input signal of the approach is cumulative oxygen uptake rate at fed-batch cultivation processes. The developed noninvasive Biomass estimation procedure was intentionally made to not depend on the selection of corresponding bioprocess/bioreactor parameters. Conclusions The precision errors, since the bioprocess start, when inoculant was injected to a bioreactor, confirmed that the approach is relevant for online Biomass state estimation. This included the lag and exponential growth phases for both E. coli and S. cerevisiae . The suggested estimation procedure is identical for both cultures. This approach improves the precision achieved by other authors without compromising the simplicity of the implementation. Moreover, the suggested approach is a candidate method to be the microorganisms’ culture invariant approach. It does not depend on any numeric initial optimization conditions, it does not require any of bioreactor parameters. No numeric stability issues of convergence occurred during multiple performance tests. All this makes this approach a potential candidate for industrial tasks with adaptive feeding control or automatic inoculations when substrate feeding profile and bioreactor parameters are not provided.
E. S. Olsvik - One of the best experts on this subject based on the ideXlab platform.
-
Correlation of Aspergillus niger broth rheological properties with Biomass Concentration and the shape of mycelial aggregates
Biotechnology and Bioengineering, 1993Co-Authors: E. S. Olsvik, K.g. Tucker, Colin R. Thomas, B. KristiansenAbstract:Aspergillus niger was grown in a 7-L chemostat at Biomass levels of 7 to 9 gL−1; dilution rates of 0.03, 0.05, 0.075, and 0.009 h−1; and dissolved oxygen tensions of 7%, 12%, and 40% of air saturation. Broth rheological measurements were made on-line, while off-line image analysis was used to measure mycelial morphology, including characterization of mycelial aggregates (clumps). Under all conditions, more than 87% of the hyphase were in clumps, the shape of which determined the rheological characteristics of the broth. In particular, the power law consistency index could be correlated with the Biomass Concentration and the roughness factor of the clumps, which describes their hairiness. A decrease in specific growth rate decreased roughness, possibly due to changes in the amount of clump breakup. However, decreases of roughness with increasing dissolved oxygen tension might rather imply some effect on hyphal–hyphal interactions within the clumps. © 1993 John Wiley & Sons, Inc.
-
Influence of oxygen tension, Biomass Concentration, and specific growth rate on the rheological properties of a filamentous fermentation broth
Biotechnology and bioengineering, 1992Co-Authors: E. S. Olsvik, B. KristiansenAbstract:The influence of oxygen tension, Biomass Concentration, and specific growth rate on the rheological properties of an Aspergillus niger fermentation broth was investigated by growing the fungus in continuous culture. The rheological properties were measured on-line using an impeller rheometer system. The effect of the specific growth rate on broth rheology was strongly influenced by the dissolved oxygen, (DO) Concentration in the broth. At DO Concentrations above 10% of saturation, K increased with the dilution rate, and at DO Concentrations below 10% of saturation, K decreased with increasing dilution rate. The largest influence of a change in the DO Concentration on the viscosity of the broth was found at the lowest growth rates and the lowest DO Concentrations. K/x, a term that gives a simple description of the structure or the morphology of the culture, was found to increase with Biomass Concentration. © 1992 John Wiley & Sons, Inc.
He Jian-yong - One of the best experts on this subject based on the ideXlab platform.
-
On-line Measurement of Biomass Concentration by Error-corrected Method
2008Co-Authors: Zhang Da-peng, He Dakuo, He Jian-yong, Lin Zhi-ling, Sang Hai-fengAbstract:A novel method is proposed to estimate the Biomass Concentration on-line by combining a mechanics model of poor extrapolation with a neural network model of unreliable parameters.An error corrected model is built to correct the output of mechanics model.It is made up of a RBF neural network that consisted of temperature,dissolved oxygen and pH and is trained by the practical values.The laboratory result shows this method can effectively increase the accuracy of forecasting Biomass Concentration.
-
Soft Sensors of Biomass Concentration in Nosiheptied Fermentation Process Based on Multiple Support Vector Machines
Computer Simulation, 2006Co-Authors: He Jian-yongAbstract:The identification of biochemical process was described with multiple support vector machine models. This concept is called ‘multimodel’ approach. During biochemical process, it is difficult to measure some variables on-line, such as Biomass Concentration. It is mostly measured off-line and cannot direct the industrial product on time because of the long delays. However, these variables can be on-line estimated using soft sensors. The multimodel approach used the measurable information on-line to build a predicting model of the Biomass Concentration. And the model was applied in the Nosiheptied fermentation. The estimated results agree well with the experimental data. It indicates that this soft sensors approach is practicably.
Renaldas Urniezius - One of the best experts on this subject based on the ideXlab platform.
-
Generic estimator of Biomass Concentration for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures based on cumulative oxygen consumption rate
Microbial cell factories, 2019Co-Authors: Renaldas Urniezius, Arnas Survyla, Dziugas Paulauskas, Vladas Algirdas Bumelis, Vytautas GalvanauskasAbstract:Background The focus of this study is online estimation of Biomass Concentration in fed-batch cultures. It describes a bioengineering software solution, which is explored for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures. The experimental investigation of both cultures presents experimental validation results since the start of the bioprocess, i.e. since the injection of inoculant solution into bioreactor. In total, four strains were analyzed, and 21 experiments were performed under varying bioprocess conditions, out of which 7 experiments were carried out with dosed substrate feeding. Development of the microorganisms’ culture invariant generic estimator of Biomass Concentration was the main goal of this research.
-
Generic estimator of Biomass Concentration for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures based on cumulative oxygen consumption rate
Microbial Cell Factories, 2019Co-Authors: Renaldas Urniezius, Arnas Survyla, Dziugas Paulauskas, Vladas Algirdas Bumelis, Vytautas GalvanauskasAbstract:Background The focus of this study is online estimation of Biomass Concentration in fed-batch cultures. It describes a bioengineering software solution, which is explored for Escherichia coli and Saccharomyces cerevisiae fed-batch cultures. The experimental investigation of both cultures presents experimental validation results since the start of the bioprocess, i.e. since the injection of inoculant solution into bioreactor. In total, four strains were analyzed, and 21 experiments were performed under varying bioprocess conditions, out of which 7 experiments were carried out with dosed substrate feeding. Development of the microorganisms’ culture invariant generic estimator of Biomass Concentration was the main goal of this research. Results The results show that stoichiometric parameters provide acceptable knowledge on the state of Biomass Concentrations during the whole cultivation process, including the exponential growth phase of both E. coli and S. cerevisiae cultures. The cell culture stoichiometric parameters are estimated by a procedure based on the Luedeking/Piret-model and maximization of entropy. The main input signal of the approach is cumulative oxygen uptake rate at fed-batch cultivation processes. The developed noninvasive Biomass estimation procedure was intentionally made to not depend on the selection of corresponding bioprocess/bioreactor parameters. Conclusions The precision errors, since the bioprocess start, when inoculant was injected to a bioreactor, confirmed that the approach is relevant for online Biomass state estimation. This included the lag and exponential growth phases for both E. coli and S. cerevisiae . The suggested estimation procedure is identical for both cultures. This approach improves the precision achieved by other authors without compromising the simplicity of the implementation. Moreover, the suggested approach is a candidate method to be the microorganisms’ culture invariant approach. It does not depend on any numeric initial optimization conditions, it does not require any of bioreactor parameters. No numeric stability issues of convergence occurred during multiple performance tests. All this makes this approach a potential candidate for industrial tasks with adaptive feeding control or automatic inoculations when substrate feeding profile and bioreactor parameters are not provided.