The use of calorimetry in biotechnology

Stockar, Urs von; Marison, I. W.

doi:10.1007/bfb0009829

Cited by 66 publications

(29 citation statements)

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“…Yet heat effects in cellular cultures often go unnoticed when one is working with conventional laboratory equipment because most of the heat released by the culture is lost to the environment too quickly to give rise to a perceivable temperature increase. This, however, is completely different in microbial cultures at large scale [5][6][7][8]. As opposed to laboratory reactors, industrial-size fermenters operate nearly adiabatically due to their much smaller surface-to-volume ratio.…”

Section: Why Should We Deal With Heat Dissipation Rates?mentioning

confidence: 99%

“…The first development of this kind was due to Cooney et al [17] and became known as "dynamic calorimetry". Meanwhile several research groups have operated bench-scale calorimeters of various types [5,[18][19][20][21][22][23][24][25][26]. Figure 4 shows one of these, based on the measuring principle known as "isothermal reaction calorimetry".…”

Section: Calorimetric Measuring Techniquesmentioning

confidence: 99%

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Biothermodynamics of live cells: a tool for biotechnology and biochemical engineering

Stockar

2010

Journal of Non-Equilibrium Thermodynamics

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The aim of this contribution is to review the application of thermodynamics to live cultures of microbial and other cells and to explore to what extent this may be put to practical use. A major focus is on energy dissipation effects in industrially relevant cultures, both in terms of heat and Gibbs energy dissipation. The experimental techniques for calorimetric measurements in live cultures are reviewed and their use for monitoring and control is discussed. A detailed analysis of the dissipation of Gibbs energy in chemotrophic growth shows that it reflects the entropy production by metabolic processes in the cells and thus also the driving force for growth and metabolism. By splitting metabolism conceptually up into catabolism and biosynthesis, it can be shown that this driving force decreases as the growth yield increases. This relationship is demonstrated by using experimental measurements on a variety of microbial strains. On the basis of these data, several literature correlations were tested as tools for biomass yield prediction. The prediction of other culture performance characteristics, including product yields for biorefinery planning, energy yields for biofuel manufacture, maximum growth rates, maintenance requirements, and threshold concentrations is also briefly reviewed.

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Section: Why Should We Deal With Heat Dissipation Rates?mentioning

confidence: 99%

Section: Calorimetric Measuring Techniquesmentioning

confidence: 99%

Biothermodynamics of live cells: a tool for biotechnology and biochemical engineering

Stockar

2010

Journal of Non-Equilibrium Thermodynamics

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“…An influence of C/N ratio in the medium on biomass composition has previously been reported for the bacteria Hyphomicrobium X (5) and Hyphomicrobium ZV620 (9) as well as for the yeasts Hansenula polymorpha (6) and Candida valida (15 principles of the calorimetric measurement procedure have been described previously (32).…”

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confidence: 97%

Growth and metabolism of Saccharomyces cerevisiae in chemostat cultures under carbon-, nitrogen-, or carbon- and nitrogen-limiting conditions

et al. 1993

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Aerobic chemostat cultures of Saccharomyces cerevisiae were performed under carbon-, nitrogen-, and dual carbon-and nitrogen-limiting conditions. The glucose concentration was kept constant, whereas the ammonium concentration was varied among different experiments and different dilution rates. It was found that both glucose and ammonium were consumed at the maximal possible rate, i.e., the feed rate, over a range of medium C/N ratios and dilution rates. To a small extent, this was due to a changing biomass composition, but much more important was the ability of uncoupling between anabolic biomass formation and catabolic energy substrate consumption. When ammonium started to limit the amount of biomass formed and hence the anabolic flow of glucose, this was totally or at least partly compensated for by an increased catabolic glucose consumption. The primary response when glucose was present in excess of the minimum requirements for biomass production was an increased rate of respiration. The calculated specific oxygen consumption rate, at D = 0.07 h-', was more than doubled when an additional nitrogen limitation was imposed on the cells compared with that during single glucose limitation. However, the maximum respiratory capacity decreased with decreasing nitrogen concentration. The saturation level of the specific oxygen consumption rate decreased from 5.5 to 6.0 mmol/g/h under single glucose limitation to about 4.0 mmol/g/h at the lowest nitrogen concentration tested. The combined result of this was that the critical dilution rate, i.e., onset of fermentation, was as low as 0.10 h-1 during growth in a medium with a low nitrogen concentration compared with 0.20 hobtained under single glucose limitation.During growth of Saccharomyces cerevisiae in a chemostat with glucose as the sole limiting substrate, energy rather than carbon limits biomass formation (7,22,29), i.e., it can be regarded as a catabolic limitation. If, on the other hand, a nitrogen source such as ammonium is used as the limiting substrate, this can instead be viewed as an anabolic limitation. Several studies, concerning bacteria, have shown that anabolism and catabolism do not seem to be tightly coupled (3,5,12,(16)(17)(18)(19)(20)25). The catabolic activity is often higher than what can be explained by the anabolic requirements for ATP when the energy source is present in excess. When glucose-grown chemostat cultures of the bacterium Klebsiella aerogenes were subjected to a limitation other than a glucose limitation, it was found that the specific respiration rate increased compared with that of glucose-limited cells. In addition, when the energy source was in excess, the cells responded by excreting a number of products more oxidized than the carbon source, i.e., not a fermentative metabolism, a phenomenon named overflow metabolism (3,12,(17)(18)(19)(20)25). K aerogenes is the most extensively studied in this respect, but several other bacteria seem to respond in a similar way (16,20). In regards to the yeast S. cerevisiae, uncoupling between c...

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“…The experiments were carried out in a modified bench-scale reaction calorimeter (Bio-RC1) of a very high sensitivity (5 mW/L) [7]. This calorimeter functions as a normal laboratory fermentor of 2 liters working volume, in which all cultivation parameters such as pressure, temperature, pH, nutrient concentrations and so on can be tightly controlled, and thus, cells can grow under defined biological conditions [3,7]. In this work, the temperature was kept at 37 °C and pH at 6.8.…”

Section: Methodsmentioning

confidence: 99%

“…This is already evident in expressions in everyday language: We tend to refer to the "warmth" of living things as opposed to the "cold inanimate world". Although from a scientific point of view there is no reason why organisms could not absorb heat and thus cool down their environment [1], the actual existence of endothermic chemotrophic growth has been considered unlikely [2][3][4] in the scientific literature. More recently, Heijnen and van Dijken [5] have, however, predicted on the basis of a theoretical energy balance that acetotrophic methanogenesis could be a net heat-uptake process.…”

Section: Heat Generation and The Driving Force For Microbial Growthmentioning

confidence: 99%

Endothermic microbial growth. A calorimetric investigation of an extreme case of entropy-driven microbial growth

Stockar

Marison

Liu

2000

Pure and Applied Chemistry

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Life is almost always associated with the generation of heat. Thus far, all chemotrophic life forms that have been studied in calorimeters were found to be exothermic. Certain literature reports have even cast doubt on the existence of endothermic growth, even though thermodynamic principles do not rule it out. The present report describes the first experiments demonstrating the actual existence of chemotrophic life forms that take up heat rather than produce it. HEAT GENERATION AND THE DRIVING FORCE FOR MICROBIAL GROWTHHeat exchange between living cells and their environment is a universal phenomenon. Life is almost always associated with the generation of heat. This is already evident in expressions in everyday language: We tend to refer to the "warmth" of living things as opposed to the "cold inanimate world". Although from a scientific point of view there is no reason why organisms could not absorb heat and thus cool down their environment [1], the actual existence of endothermic chemotrophic growth has been considered unlikely [2][3][4] in the scientific literature. More recently, Heijnen and van Dijken [5] have, however, predicted on the basis of a theoretical energy balance that acetotrophic methanogenesis could be a net heat-uptake process.The driving force for microbial growth is the change of Gibbs energy occuring in the growth medium as a result of microbial metabolism. Growing microorganisms consume high Gibbs energy foodstuffs and release waste products of low Gibbs energy. It can be shown that the decrease of Gibbs energy resulting from this exchange of metabolites reflects the total rate of entropy production generated by all the irreversible processes that make life and growth possible:(1) On average, the products must have a lower Gibbs energy than the substrates, even though one of the "products" of metabolism is new biomass.The driving force for growth is thus the dissipation of Gibbs energy and may be described as a ∆G for the overall growth reaction. It must be negative for growth to occur. The heat release of the growth reaction depends on the respective ∆H value. Although, as already pointed out, there is no thermodynamic constraint that would prevent ∆H from being positive, it is negative in an overwhelming majority of cases and thus contributes to the driving force according to (2) *Plenary lecture presented at the 16

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The use of calorimetry in biotechnology

Cited by 66 publications

References 58 publications

Biothermodynamics of live cells: a tool for biotechnology and biochemical engineering

Biothermodynamics of live cells: a tool for biotechnology and biochemical engineering

Growth and metabolism of Saccharomyces cerevisiae in chemostat cultures under carbon-, nitrogen-, or carbon- and nitrogen-limiting conditions

Endothermic microbial growth. A calorimetric investigation of an extreme case of entropy-driven microbial growth

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