Heat Production and Growth Kinetics of E. coli K12 from Flow Calorimetric Measurements on Chemostat Cultures

1989 ◽  
Vol 44 (11-12) ◽  
pp. 1036-1048 ◽  
Author(s):  
H. P. Leiseifer
Keyword(s):  
Heat Production ◽  
Growth Rates ◽  
Specific Growth ◽  
Batch Cultures ◽  
E Coli ◽  
Chemostat Cultures ◽  
Basic Parameters ◽  
Specific Growth Rates ◽  
The Relationship ◽  
Kinetics Of

The heat production of E. coli K12 growing aerobically in glucose limited chemostat cultures is determined in the range of specific growth rates μ ( = dilution rates D) from 0,058 h-1 to 0.852 h-1 for two different glucose concentrations Se in the instream of the chemostat. namely Se1=0.3182 g·1-1 and Se2 = 0.6364 g·1-1. Heat production Q and biomass production P per unit of culture volume show well correlated patterns for Se1 and Se2. For Se1 the highest value Q actually measured is 443-10-3 W·1-1 at D = 0.74 h-1 with P = 0.068 g·1-1·h-1 and for Se2 593·10-3 W·1-1 at D = 0.497 h-1 with P = 0.108 g·1-1·h-1. Heat production QB per unit of biomass appears to be independent of Se at least up to D - 0.5 h-1.At higher D there is strong indication that QB possesses a real maximum. The highest value of QB actually measured is 4.8 W·g-1 at D = 0.74 h-1. For Se1 and Se2 there were significantly higher specific growth rates verified in chemostat culture than μmaxBatch= 0.717 h-1 which is the maximum specific growth rate in comparable, unlimited batch cultures. The real maximum of QB is estimated to be in the vicinity of μmaxBatch. This suggests the hypothesis of a maximum principle for the growth in batch culture. For Se1 a closed analytical expression is derived for the relationship between μ and the substrate concentration S. μ[S] features a S-shaped characteristic with μmaxChemostat= 0.905 h-1; 1/2 μmaxChemostat is reached at S = 2.85·10-3 g·1-1. Three basic parameters which characterize the overall metabolism of the cells, namely the heat released per unit of substrate consumed, (Qs, the effective yield of biomass, Yeff, and μmaxChemostat are identified to depend on Se.

scholarly journals Endoplasmic Reticulum-Associated rht-PA Processing in CHO Cells: Influence of Mild Hypothermia and Specific Growth Rates in Batch and Chemostat Cultures

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0144224 ◽  
Author(s):  
Mauricio Vergara ◽  
Julio Berrios ◽  
Irene Martínez ◽  
Alvaro Díaz-Barrera ◽  
Cristian Acevedo ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Growth Rates ◽  
Cho Cells ◽  
Specific Growth ◽  
Mild Hypothermia ◽  
Chemostat Cultures ◽  
Specific Growth Rates

Morphogenetic expression of Arthrobacter globiformis 425 in continuous culture with carbon or biotin limitation

1978 ◽  
Vol 24 (1) ◽  
pp. 28-30 ◽  
Author(s):  
Adrian P. Wills ◽  
E. C. S. Chan
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Specific Growth ◽  
Normal Growth ◽  
Arthrobacter Globiformis ◽  
Glucose Limitation ◽  
Abnormal Morphology ◽  
Chemostat Cultures ◽  
Specific Growth Rates ◽  
Biotin Limitation

When deprived of biotin, Arthrobacter globiformis 425 exhibits abnormal morphology (large, branched forms of variable size) and a retardation of its normal growth rate. In chemostat cultures, when cells were grown under glucose limitation, the morphology was normal (coccoids or rods) at specific growth rates between 0.05 and 0.125 h−1 (doubling times between 14 and 5.5 h, respectively) at 25 °C. The coccoid-to-rod morphogenesis occurs at a specific growth rate of 0.11 h−1. At the same specific growth rates and temperature, but under biotin limitation, abnormal morphology was observed.

scholarly journals Effect of Pulsed Electric Fields on the Growth and Acidification Kinetics of Lactobacillus delbrueckii Subsp. bulgaricus

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1146
Author(s):  
Kaidi Peng ◽  
Mohamed Koubaa ◽  
Olivier Bals ◽  
Eugène Vorobiev
Keyword(s):  
Electric Fields ◽  
Growth Rates ◽  
Specific Growth ◽  
Pulsed Electric Fields ◽  
Lactobacillus Delbrueckii ◽  
Accelerated Growth ◽  
Specific Growth Rates ◽  
The Impact ◽  
Kinetics Of ◽  
Lactobacillus Delbrueckii Subsp

The aim of this work was to investigate the effect of pulsed electric fields (PEF) on the growth and acidification kinetics of Lactobacillus delbrueckii subsp. bulgaricus CFL1 during fermentation. The PEF treatments were applied during the fermentation process using a recirculation pump and a PEF treatment chamber coupled with a PEF generator. The medium flow rate through the chamber was first optimized to obtain the same growth and acidification kinetics than the control fermentation without medium recirculation. Different PEF intensities (60–428 V cm−1) were then applied to the culture medium to study the impact of PEF on the cells’ behavior. The growth and acidification kinetics were recorded during the fermentation and the specific growth rates µ, pH, and acidification rate (dpH/dt) were assessed. The results obtained showed a biphasic growth by applying high PEF intensities (beyond 285 V cm−1) with the presence of two maximal specific growth rates and a decrease in the acidification activities. It was demonstrated that the cells were stressed during the PEF treatment, but presented an accelerated growth after stopping it, leading thereby to similar absorbance and pH at the end of the fermentation. These results show the great potential of PEF technology to be applied to generate low acidified products by performing PEF-assisted fermentations.

scholarly journals Pichia pastoris Exhibits High Viability and a Low Maintenance Energy Requirement at Near-Zero Specific Growth Rates

2016 ◽  
Vol 82 (15) ◽  
pp. 4570-4583 ◽  
Author(s):  
Corinna Rebnegger ◽  
Tim Vos ◽  
Alexandra B. Graf ◽  
Minoska Valli ◽  
Jack T. Pronk ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Growth Rates ◽  
Specific Growth ◽  
Energy Requirement ◽  
Maintenance Energy ◽  
Content Type ◽  
Chemostat Cultures ◽  
Zero Growth ◽  
Maintenance Energy Requirement ◽  
Specific Growth Rates

ABSTRACTThe yeastPichia pastorisis a widely used host for recombinant protein production. Understanding its physiology at extremely low growth rates is a first step in the direction of decoupling product formation from cellular growth and therefore of biotechnological relevance. Retentostat cultivation is an excellent tool for studying microbes at extremely low specific growth rates but has so far not been implemented forP. pastoris. Retentostat feeding regimes were based on the maintenance energy requirement (mS) and maximum biomass yield on glucose (YX/Smax) estimated from steady-state glucose-limited chemostat cultures. Aerobic retentostat cultivation enabled reproducible, smooth transitions from a specific growth rate (μ) of 0.025 h−1to near-zero specific growth rates (μ < 0.001 h−1). At these near-zero specific growth rates, viability remained at least 97%. The value ofmSat near-zero growth rates was 3.1 ± 0.1 mg glucose per g biomass and h, which was 3-fold lower than themSestimated from faster-growing chemostat cultures. This difference indicated thatP. pastorisreduces its maintenance energy requirement at extremely low μ, a phenomenon not previously observed in eukaryotes. Intracellular levels of glycogen and trehalose increased, while μ progressively declined during retentostat cultivation. Transcriptional reprogramming toward zero growth included the upregulation of many transcription factors as well as stress-related genes and the downregulation of cell cycle genes. This study underlines the relevance of comparative analysis of maintenance energy metabolism, which has an important impact on large-scale industrial processes.IMPORTANCEThe yeastPichia pastorisnaturally lives on trees and can utilize different carbon sources, among them glucose, glycerol, and methanol. In biotechnology, it is widely used for the production of recombinant proteins. For both the understanding of life in its natural habitat and optimized production processes, a better understanding of cell physiology at an extremely low growth rate would be of extraordinary value. Therefore, we have grownP. pastorisin a retentostat, which allows the cultivation of metabolically active cells even at zero growth. Here we reached doubling times as long as 38 days and found thatP. pastorisdecreases its maintenance energy demand 3-fold during very slow growth, which enables it to survive with a much lower substrate supply than baker's yeast.

Quantitative relationships for specific growth rates and macromolecular compositions of Mycobacterium tuberculosis, Streptomyces coelicolor A3(2) and Escherichia coli B/r: an integrative theoretical approach

Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1413-1426 ◽  
Author(s):  
Robert A. Cox
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Mycobacterium Tuberculosis ◽  
Growth Rates ◽  
Specific Growth ◽  
Streptomyces Coelicolor ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
E Coli ◽  
Specific Growth Rates

Further understanding of the physiological states of Mycobacterium tuberculosis and other mycobacteria was sought through comparisons with the genomic properties and macromolecular compositions of Streptomyces coelicolor A3(2), grown at 30 °C, and Escherichia coli B/r, grown at 37 °C. A frame of reference was established based on quantitative relationships observed between specific growth rates (μ) of cells and their macromolecular compositions. The concept of a schematic cell based on transcription/translation coupling, average genes and average proteins was developed to provide an instantaneous view of macromolecular synthesis carried out by cells growing at their maximum rate. It was inferred that the ultra-fast growth of E. coli results from its ability to increase the average number of rRNA (rrn) operons per cell through polyploidy, thereby increasing its capacity for ribosome synthesis. The maximum growth rate of E. coli was deduced to be limited by the rate of uptake and consumption of nutrients providing energy. Three characteristic properties of S. coelicolor A3(2) growing optimally (μ=0·30 h−1) were identified. First, the rate of DNA replication was found to approach the rate reported for E. coli (μ=1·73 h−1); secondly, all rrn operons were calculated to be fully engaged in precursor-rRNA synthesis; thirdly, compared with E. coli, protein synthesis was found to depend on higher concentrations of ribosomes and lower concentrations of aminoacyl-tRNA and EF-Tu. An equation was derived for E. coli B/r relating μ to the number of rrn operons per genome. Values of μ=0·69 h−1 and μ=1·00 h−1 were obtained respectively for cells with one or two rrn operons per genome. Using the author's equation relating the number of rrn operons per genome to maximum growth rate, it is expected that M. tuberculosis with one rrn operon should be capable of growing much faster than it actually does. Therefore, it is suggested that the high number of insertion sequences in this species attenuates growth rate to still lower values.

Assessment of correlation between physiological states of Escherichia coli cells and their susceptibility to chlorine using flow cytometry

2013 ◽  
Vol 13 (4) ◽  
pp. 1056-1062 ◽  
Author(s):  
Saeid Rezaeinejad ◽  
Volodymyr Ivanov
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Growth Rates ◽  
Specific Growth ◽  
Bacterial Cells ◽  
Tetrazolium Chloride ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Cell Subpopulations ◽  
Specific Growth Rates

The physiological differences of individual cells of bacterial population may imply the existence of cell subpopulations with different sensitivity to chlorine, which may affect the efficiency of drinking water disinfection. The susceptibility of individual bacterial cells to chlorine was examined using flow cytometry. The inactivation of Escherichia coli cells by chlorine in the populations with specific growth rates of 0.2 and 0.9 h−1 was assessed using various viability indicators. Viability of bacterial cells was evaluated using membrane integrity propidium iodide (PI) dye, respiratory activity indicator of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and membrane potential probe of DiBAC4(3). It was found that there were cell subpopulations of E. coli with different levels of susceptibility to chlorine. E. coli cell population with higher specific growth rate was more susceptible to chlorine. The CT values for inactivation of 99% of cells (CT99) in populations of E. coli with specific growth rates of 0.9 and 0.2 h−1 were 0.06 and 0.09 mg min l−1, respectively. Flow cytometry could be used to study the sensitivity of bacterial cells to the chemical agents.

scholarly journals Contribution of Complex I NADH Dehydrogenase to Respiratory Energy Coupling in Glucose-Grown Cultures of Ogataea parapolymorpha

2020 ◽  
Vol 86 (15) ◽  
Author(s):  
Hannes Juergens ◽  
Xavier D. V. Hakkaart ◽  
Jildau E. Bras ◽  
André Vente ◽  
Liang Wu ◽  
...  
Keyword(s):  
Growth Rates ◽  
Complex I ◽  
Energy Coupling ◽  
Content Type ◽  
Batch Cultures ◽  
Cell Factories ◽  
Chemostat Cultures ◽  
Biomass Yields ◽  
Nadh Dehydrogenases ◽  
Specific Growth Rates

ABSTRACT The thermotolerant yeast Ogataea parapolymorpha (formerly Hansenula polymorpha) is an industrially relevant production host that exhibits a fully respiratory sugar metabolism in aerobic batch cultures. NADH-derived electrons can enter its mitochondrial respiratory chain either via a proton-translocating complex I NADH-dehydrogenase or via three putative alternative NADH dehydrogenases. This respiratory entry point affects the amount of ATP produced per NADH/O2 consumed and therefore impacts the maximum yield of biomass and/or cellular products from a given amount of substrate. To investigate the physiological importance of complex I, a wild-type O. parapolymorpha strain and a congenic complex I-deficient mutant were grown on glucose in aerobic batch, chemostat, and retentostat cultures in bioreactors. In batch cultures, the two strains exhibited a fully respiratory metabolism and showed the same growth rates and biomass yields, indicating that, under these conditions, the contribution of NADH oxidation via complex I was negligible. Both strains also exhibited a respiratory metabolism in glucose-limited chemostat cultures, but the complex I-deficient mutant showed considerably reduced biomass yields on substrate and oxygen, consistent with a lower efficiency of respiratory energy coupling. In glucose-limited retentostat cultures at specific growth rates down to ∼0.001 h−1, both O. parapolymorpha strains showed high viability. Maintenance energy requirements at these extremely low growth rates were approximately 3-fold lower than estimated from faster-growing chemostat cultures, indicating a stringent-response-like behavior. Quantitative transcriptome and proteome analyses indicated condition-dependent expression patterns of complex I subunits and of alternative NADH dehydrogenases that were consistent with physiological observations. IMPORTANCE Since popular microbial cell factories have typically not been selected for efficient respiratory energy coupling, their ATP yields from sugar catabolism are often suboptimal. In aerobic industrial processes, suboptimal energy coupling results in reduced product yields on sugar, increased process costs for oxygen transfer, and volumetric productivity limitations due to limitations in gas transfer and cooling. This study provides insights into the contribution of mechanisms of respiratory energy coupling in the yeast cell factory Ogataea parapolymorpha under different growth conditions and provides a basis for rational improvement of energy coupling in yeast cell factories. Analysis of energy metabolism of O. parapolymorpha at extremely low specific growth rates indicated that this yeast reduces its energy requirements for cellular maintenance under extreme energy limitation. Exploration of the mechanisms for this increased energetic efficiency may contribute to an optimization of the performance of industrial processes with slow-growing eukaryotic cell factories.

scholarly journals Specific Growth Rate Determines the Sensitivity of Escherichia coli to Thermal, UVA, and Solar Disinfection

2006 ◽  
Vol 72 (4) ◽  
pp. 2586-2593 ◽  
Author(s):  
Michael Berney ◽  
Hans-Ulrich Weilenmann ◽  
Julian Ihssen ◽  
Claudio Bassin ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Rates ◽  
Specific Growth ◽  
E Coli ◽  
Mild Heat ◽  
Uva Light ◽  
Specific Growth Rates ◽  
Slow Growing

ABSTRACT Knowledge about the sensitivity of the test organism is essential for the evaluation of any disinfection method. In this work we show that sensitivity of Escherichia coli MG1655 to three physical stresses (mild heat, UVA light, and sunlight) that are relevant in the disinfection of drinking water with solar radiation is determined by the specific growth rate of the culture. Batch- and chemostat-cultivated cells from cultures with similar specific growth rates showed similar stress sensitivities. Generally, fast-growing cells were more sensitive to the stresses than slow-growing cells. For example, slow-growing chemostat-cultivated cells (D = 0.08 h−1) and stationary-phase bacteria from batch culture that were exposed to mild heat had very similar T 90 (time until 90% of the population is inactivated) values (T 90, chemostat = 2.66 h; T 90, batch = 2.62 h), whereas T 90 for cells growing at a μ of 0.9 h−1 was 0.2 h. We present evidence that the stress sensitivity of E. coli is correlated with the intracellular level of the alternative sigma factor RpoS. This is also supported by the fact that E. coli rpoS mutant cells were more stress sensitive than the parent strain by factors of 4.9 (mild heat), 5.3 (UVA light), and 4.1 (sunlight). Furthermore, modeling of inactivation curves with GInaFiT revealed that the shape of inactivation curves changed depending on the specific growth rate. Inactivation curves of cells from fast-growing cultures (μ = 1.0 h−1) that were irradiated with UVA light showed a tailing effect, while for slow-growing cultures (μ = 0.3 h−1), inactivation curves with shoulders were obtained. Our findings emphasize the need for accurate reporting of specific growth rates and detailed culture conditions in disinfection studies to allow comparison of data from different studies and laboratories and sound interpretation of the data obtained.

scholarly journals Effect of Environmental Factors on Growth Kinetics of Biocontrol Agent Bacillus thuringiensis Bacterium using 2L and 5L A+ Sartorius Stedim Biostat® Fermentation Systems

2020 ◽  
Vol 2 (6) ◽  
Author(s):  
C. S. Richardson ◽  
D. Upadhyay ◽  
S. Mandjiny ◽  
L. Holmes
Keyword(s):  
Growth Rate ◽  
Bacillus Thuringiensis ◽  
Growth Kinetics ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Doubling Time ◽  
Specific Growth ◽  
Optimal Conditions ◽  
Specific Growth Rates ◽  
Kinetics Of

Bacillus thuringiensis (Bt) is a soil-dwelling, Gram-positive bacterium that is used as a biological pesticide and used to genetically engineer plants due to the toxic proteins it produces. B. thuringiensis was studied in batch cultures to determine the specific growth rates and doubling times. The purpose of this experiment was to research the growth kinetics of Bacillus thuringiensis in a 2L bioreactor and a 5L bioreactor containing growth media at different environmental conditions. Fermentation parameters were controlled by utilizing a Sartorius Stedim Biostat® A+ bioreactor system for bacterial growth. The environmental conditions included temperature, agitation, and aeration. The specific growth rates of B. thuringiensis were determined. The optimal conditions for the 2L bioreactor were 200 RPM, 30°C, 1.5 VVM, and with the highest specific growth rate 0.30 hr and the shortest doubling time 2.3 hr. For the 5L bioreactor, the optimal conditions were 150 RPM, 30°C, 1.5 VVM, and with the highest specific growth rate 1.2 hr and the fastest doubling time 0.6 hr.

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