Interrelationship among specific rates of cell growth, substrate consumption, and metabolite formation in some simple microbial reactions producing primary metabolites

1981 ◽  
Vol 23 (6) ◽  
pp. 1373-1387 ◽  
Author(s):  
Tsuneo Yamané ◽  
Takeshi Shiotani
Keyword(s):  
Cell Growth ◽  
Growth Substrate ◽  
Substrate Consumption ◽  
Metabolite Formation ◽  
Primary Metabolites

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.

scholarly journals Adenine Addition Restores Cell Viability and Butanol Production in Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) Cultivated at 37°C

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Keiji Kiyoshi ◽  
Sohei Kawashima ◽  
Kosuke Nobuki ◽  
Toshimori Kadokura ◽  
Atsumi Nakazato ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cell Viability ◽  
Spore Formation ◽  
Butanol Production ◽  
Metabolomic Analysis ◽  
Primary Metabolites ◽  
Content Type ◽  
Atp Levels ◽  
Wide Range ◽  
Multiple Primary

ABSTRACT We have developed butanol-producing consolidated bioprocessing from cellulosic substrates through coculture of cellulolytic clostridia and butanol-producing Clostridium saccharoperbutylacetonicum strain N1-4. However, the butanol fermentation by strain N1-4 (which has an optimal growth temperature of 30°C) is sensitive to the higher cultivation temperature of 37°C; the nature of this deleterious effect remains unclear. Comparison of the intracellular metabolites of strain N1-4 cultivated at 30°C and 37°C revealed decreased levels of multiple primary metabolites (notably including nucleic acids and cofactors) during growth at the higher temperature. Supplementation of the culture medium with 250 mg/liter adenine enhanced both cell growth (with the optical density at 600 nm increasing from 4.3 to 10.2) and butanol production (increasing from 3.9 g/liter to 9.6 g/liter) at 37°C, compared to those obtained without adenine supplementation, such that the supplemented 37°C culture exhibited growth and butanol production approaching those observed at 30°C in the absence of adenine supplementation. These improved properties were based on the maintenance of cell viability. We further showed that adenine supplementation enhanced cell viability during growth at 37°C by maintaining ATP levels and inhibiting spore formation. This work represents the first demonstration (to our knowledge) of the importance of adenine-related metabolism for clostridial butanol production, suggesting a new means of enhancing target pathways based on metabolite levels. IMPORTANCE Metabolomic analysis revealed decreased levels of multiple primary metabolites during growth at 37°C, compared to 30°C, in C. saccharoperbutylacetonicum strain N1-4. We found that adenine supplementation restored the cell growth and butanol production of strain N1-4 at 37°C. The effects of adenine supplementation reflected the maintenance of cell viability originating from the maintenance of ATP levels and the inhibition of spore formation. Thus, our metabolomic analysis identified the depleted metabolites that were required to maintain cell viability. Our strategy, which is expected to be applicable to a wide range of organisms, permits the identification of the limiting metabolic pathway, which can serve as a new target for molecular breeding. The other novel finding of this work is that adenine supplementation inhibits clostridial spore formation. The mechanism linking spore formation and metabolomic status in butanol-producing clostridia is expected to be the focus of further research.

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 Kinetic Studies on Fermentative Production of Biofuel from Synthesis Gas UsingClostridium ljungdahlii

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Maedeh Mohammadi ◽  
Abdul Rahman Mohamed ◽  
Ghasem D. Najafpour ◽  
Habibollah Younesi ◽  
Mohamad Hekarl Uzir
Keyword(s):  
Cell Growth ◽  
Synthesis Gas ◽  
Uptake Rate ◽  
Kinetic Studies ◽  
Product Formation ◽  
Volterra Model ◽  
Substrate Uptake ◽  
Growth Substrate ◽  
Clostridium Ljungdahlii ◽  
Batch Bioreactors

The intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium,Clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. A dual-substrate growth kinetic model using Luong for CO and Monod for H2was used to describe the growth kinetics of the bacterium on these substrates. The maximum specific growth rate (μmax= 0.195 h−1) and Monod constants for CO (Ks,CO= 0.855 atm) and H2(Ks,H2= 0.412 atm) were obtained. This model also accommodated the CO inhibitory effects on cell growth at high CO partial pressures, where no growth was apparent at high dissolved CO tensions (PCO∗>0.743 atm). The Volterra model, Andrews, and modified Gompertz were, respectively, adopted to describe the cell growth, substrate uptake rate, and product formation. The maximum specific CO uptake rate (qmax= 34.364 mmol/gcell/h), CO inhibition constant (KI= 0.601 atm), and maximum rate of ethanol (Rmax= 0.172 mmol/L/h atPCO= 0.598 atm) and acetate (Rmax= 0.096 mmol/L/h atPCO= 0.539 atm) production were determined from the applied models.

Pharmacologically tunable polyethylene-glycol-based cell growth substrate

2013 ◽  
Vol 9 (9) ◽  
pp. 8272-8278 ◽  
Author(s):  
Raphael J. Gübeli ◽  
Dougal Laird ◽  
Martin Ehrbar ◽  
Benjamin S. Ritter ◽  
Thorsten Steinberg ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Cell Growth ◽  
Growth Substrate
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