The Transient Kinetics ofEscherichia coliChorismate Synthase:  Substrate Consumption, Product Formation, Phosphate Dissociation, and Characterization of a Flavin Intermediate†

Biochemistry ◽  
1996 ◽  
Vol 35 (30) ◽  
pp. 9907-9916 ◽  
Author(s):  
Stephen Bornemann ◽  
David J. Lowe ◽  
Roger N. F. Thorneley
Keyword(s):  
Product Formation ◽  
Transient Kinetics ◽  
Substrate Consumption

Improved Dynamic System of Microbial Continuous Fermentation and its Parameter Identification

2014 ◽  
Vol 633-634 ◽  
pp. 545-549
Author(s):  
Hong Li Xiao ◽  
Lan Zhang Chong ◽  
Fei Li Hang ◽  
Wang Yong
Keyword(s):  
Dynamic System ◽  
Consumption Rate ◽  
Continuous Fermentation ◽  
Formation Rate ◽  
Product Formation ◽  
Cellular Growth ◽  
Specific Substrate ◽  
Substrate Consumption ◽  
Specific Product ◽  
Product Formation Rate

In this paper, the nonlinear dynamic system of microbe continuous fermentation products 1,3-propanediol (1,3-PD) is rewritten by improving the specific cellular growth rate, specific substrate consumption rate and specific product formation rate. Firstly, under the condition of substrate glycol excess and active trans-membrane transport, according to the dynamic behavior the fermentation process, we consider the glycerol and 1,3–PD concentration within the cell, and improve the specific cellular growth rate, specific substrate consumption rate and specific product formation rate, then rewrite the dynamic system of microbial continuous fermentation process. Secondly, taking the dynamic system as main constraint condition, we establish the parameter identification model and prove the existence of the optimal solution. Lastly, the numerical results calculated by particle swarm algorithm show that the improved model is suitable for describe the dynamic behavior of 1,3-PD, but is not accurate enough for by-products.

scholarly journals Application Of The Z And Laplace Transforms To Panification Yeast Production Using An Airlift Bioreactor

2020 ◽  
Author(s):  
Arnaldo Silva Oliveira ◽  
Juan C. B. Neto ◽  
Igor J. B. Santos ◽  
Edson R. Nucci
Keyword(s):  
Cell Growth ◽  
Product Formation ◽  
Laplace Transforms ◽  
Discrete Models ◽  
Average Error ◽  
Growth Substrate ◽  
Substrate Consumption ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mathematical Techniques ◽  
Discrete Time Models

Abstract The Z- and Laplace transforms are mathematical techniques applied to solve difference equations and differential equations, respectively. Mathematical models used to describe cell growth, substrate consumption and product formation in bioprocesses can be represented by these types of equations. Thus, in this work, the fermentation process of the yeast Saccharomyces cerevisiae was modeled using different models from the literature, and the Z- and Laplace transforms were applied to solve the equations. Once the equations were solved, the models were represented in state space and simulated in Octave® software. Finally, the models were compared to experimental data from previous studies and to each other. Verhulst was the model that best described the process, with an average error of 4.74% for cell growth and 13.9% for substrate consumption. This work is unprecedented since no works that use the Z transform and discrete models for the representation of fermentation of this yeast were found in the literature. Even more importantly, this work proved that discrete-time models can be applied to bioprocesses with the same precision as continuous-time models.

Immobilized cell microchannel bioreactor for evaluating fermentation characteristics of mixed substrate consumption and product formation

2012 ◽  
Vol 47 (6) ◽  
pp. 1011-1015 ◽  
Author(s):  
Tae Young Seo ◽  
Ki Won Eum ◽  
Sung Ok Han ◽  
Seung Wook Kim ◽  
Ji Hyeon Kim ◽  
...  
Keyword(s):  
Product Formation ◽  
Immobilized Cell ◽  
Substrate Consumption ◽  
Mixed Substrate

The Study of the Kinetic Model of Halomonas Salina Fermenting Ectoine

2013 ◽  
Vol 781-784 ◽  
pp. 647-652
Author(s):  
Shuang Gao ◽  
Ling Hua Zhang ◽  
Qing Chen ◽  
Lin Bai ◽  
Ya Jun Lang
Keyword(s):  
Cell Growth ◽  
Kinetic Model ◽  
Monosodium Glutamate ◽  
Biomass Concentration ◽  
Correlation Coefficients ◽  
Kinetic Mechanism ◽  
Product Formation ◽  
Substrate Consumption ◽  
Nonlinear Fitting ◽  
Potential Applications

Ectoine had important physiological functions and superior potential applications, so the study of ectoine was extensively attented. This article was related to kinetic models of cell growth, product formation and substrate consumption, which was not only established according to the characteristics of ectoine batch fermentation by Halomonas salina DSM 5928 but also obtained the kinetic parameters by the nonlinear fitting method in the Microcal Origin software. Logistic, Luedeking-Piret and Luedeking-Piret-like equations was applied to analyze the cell growth, the ectoine formation and the substrate consumption by the kinetic model，respectively. The results between calculated values and experimental data were coincident. By fitting, correlation coefficients R2 were ≥ 0.989. The fermentation conditions of ectoine were analyzed according to the model. The results showed that ectoine productivity (0.28 g/L/h) was the highest when initial monosodium glutamate concentration (S0) was 60 g/L. However, when S0 was 80 g/L, the ectoine concentration was maximal, i.e., 7.59 g/L. The research suggested that ectoine formation belonged to the mixed kinetic mechanism of cell growth and biomass concentration, while the ectoine production mainly depended on instantaneous biomass concentration. The fermentation method for improving ectoine concentration was further proved. The established kinetic model will be of significant value to provide the optimal conditions of present process.

scholarly journals Characterization of the Sporulation Control Protein SsgA by Use of an Efficient Method To Create and Screen Random Mutant Libraries in Streptomycetes

2007 ◽  
Vol 73 (7) ◽  
pp. 2085-2092 ◽  
Author(s):  
Bjørn A. Traag ◽  
Nicolas Seghezzi ◽  
Erik Vijgenboom ◽  
Gilles P. van Wezel
Keyword(s):  
Efficient Method ◽  
Streptomyces Coelicolor ◽  
Product Formation ◽  
Single Amino Acid ◽  
Poor Growth ◽  
Microtiter Plates ◽  
Enhanced Expression ◽  
Major Bottleneck ◽  
Carboxy Terminal

ABSTRACT Filamentous actinomycetes are commercially widely used as producers of natural products. However, the mycelial lifestyle of actinomycetes has been a major bottleneck in their commercialization, and screening is difficult due to their poor growth on microtiter plates. We previously demonstrated that the enhanced expression of the cell division activator protein SsgA results in the fragmented growth of streptomycetes, with enhanced growth rates and improved product formation. We here describe a novel and efficient method to create, maintain, and screen mutant libraries in streptomycetes and the application of this method for the functional analysis of Streptomyces coelicolor ssgA. The variants were amplified directly from deep-frozen biomass suspensions. Around 800 ssgA variants, including single-amino-acid-substitution mutants corresponding to more than half of all SsgA residues, were analyzed for their abilities to restore sporulation to an ssgA mutant. The essential residues were clustered in three main sections, and hardly any were in the carboxy-terminal third of the protein. The majority of the crucial residues were conserved among all SsgA-like proteins (SALPs). However, the essential residues L29, D58, and S89 were conserved only in SsgA orthologues and not in other SALPs, suggesting an SsgA-specific function.

Quantitation of superoxide generation and substrate utilization by vascular NAD(P)H oxidase

2002 ◽  
Vol 282 (2) ◽  
pp. H466-H474 ◽  
Author(s):  
Heraldo P. Souza ◽  
Xiaoping Liu ◽  
Alexandre Samouilov ◽  
Periannan Kuppusamy ◽  
Francisco R. M. Laurindo ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Time Course ◽  
Spin Trapping ◽  
Superoxide Generation ◽  
Substrate Consumption ◽  
Similar Time ◽  
Paramagnetic Resonance ◽  
Resonance Spin ◽  
Electron Paramagnetic

In vascular tissues, an NAD(P)H oxidase is the main source of superoxide; however, there has been much uncertainty regarding its activity and the levels of superoxide it generates. This problem has limited overall progress in this field. Therefore, studies were performed and techniques developed to quantitatively assess the function of the vascular NAD(P)H oxidase, measuring its rate of superoxide production and substrate consumption in rat aortic homogenates and intact segments. NADPH/NADH oxidation was measured spectrophotometrically, and oxygen consumption was measured by electrochemical probe. Superoxide was detected and quantitated by electron paramagnetic resonance spin trapping. Under basal conditions, superoxide generation and oxygen consumption were negligible. After addition of NADPH or NADH (0.1 mM), superoxide was generated at rates of 0.41 ± 0.03 or 0.36 ± 0.04 nmol · mg protein−1· min−1, respectively. Oxygen was consumed with a similar time course at rates of 1.5 ± 0.2 or 1.3 ± 0.3 nmol · mg protein−1· min−1, and NADPH or NADH were oxidized at rates of 1.8 ± 0.4 and 1.5 ± 0.3 nmol · mg protein−1· min−1, respectively. In intact aortic rings, superoxide was generated with rates of 4.0 ± 0.7 or 3.7 ± 0.7 pmol · mg tissue−1· min−1, whereas oxygen was consumed at rates of 22.1 ± 5.0 or 14.5 ± 3.3 pmol · mg tissue−1· min−1, for NADPH or NADH, respectively. These values are lower than those previously measured using lucigenin, which uncouples flavoenzymes, triggering additional superoxide generation. This quantitative approach for characterization of the vascular NAD(P)H oxidase activity should facilitate the further identification and cellular characterization of this enzyme(s) and its functional and signaling roles.

Competitive Inhibition of Propionibacterium acidipropionici by Mixed Culturing with Lactobacillus helveticus

1994 ◽  
Vol 57 (4) ◽  
pp. 341-344 ◽  
Author(s):  
A. PEREZ CHAIA ◽  
A. M. STRASSER DE SAAD ◽  
A. PESCE DE RUIZ HOLGADO ◽  
G. OLIVER
Keyword(s):  
Specific Growth ◽  
Competitive Inhibition ◽  
Product Formation ◽  
Lactobacillus Helveticus ◽  
Substrate Consumption ◽  
Propionibacterium Acidipropionici ◽  
Propionic Acid Bacteria ◽  
Lactate Utilization ◽  
Consumption Coefficient ◽  
Specific Growth Rates

Lactobacillus helveticus and Propionibacterium acidipropionici were grown in pure and mixed cultures in a complex medium to assess the associative interaction. The specific growth rates, substrate consumption coefficient, substrate utilization and product formation rates were determined in each case. Propionibacterium acidipropionici utilized glucose preferably when it grew in a medium containing a mixture of glucose and lactate. Its growth rate was higher on glucose than on lactate in pure culture. However, lactic acid was the substrate utilized by propionibacteria in the associative growth. The fast pH reduction produced by the growth of lactobacilli and the slow lactate utilization by propionibacteria in mixed culture determined the inhibition of propionic acid bacteria in associative growth.

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