Dependence of release of nucleotides from fungi on fermentor turbine speed

Ujcová, E.; Fencl, Z.; Musílková, M.; Seichert, L.

doi:10.1002/bit.260220119

Cited by 58 publications

(14 citation statements)

References 3 publications

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“…Second, it has not been possible to dissociate the influence of agitation from mass transfer effects. The dependence of product formation rates on impeller-generated fluid dynamic stresses has been observed for a wide variety of filamentous fungi (Ujcova et al, 1980;Vardar and Lilly, 1982;Smith et al, 1990;Braun and Vecht-Lifshitz, 1991;Märkl et al, 1991;Merchuk, 1991). There are also reports that mycelial fragmentation depends on the physiological state of the microorganisms (Smith et al, 1990;Paul et al, 1994).…”

Section: -4 Mycelial Fermentationsmentioning

confidence: 90%

“…However, provided that these factors can be controlled and optimized, agitation-induced fragmentation, apart from growth, is considered to be one of the most important factors influencing mycelial morphology (especially in the design, operation, and scale-up of fungal fermentations). Although many studies have been conducted to investigate the effects of hydrodynamic forces on mycelial morphology and productivity (Dion et al, 1954;Ujcova et al, 1980;Metz et al, 1981;van Suijdam and Metz, 1981;Reuss, 1988;Smith et al, 1990;Makagiansar et al, 1993;Ayazi Shamlou et al, 1994;Nielsen et al, 1995), they generally suffer from two limitations. First, due to the lack of suitable methods for characterizing clumps (Tucker et al, 1992), only the freely dispersed form has been considered, although it may only account for only a small fraction of the biomass (Tucker et al, 1992;Jüsten et al, 1996).…”

Section: -4 Mycelial Fermentationsmentioning

confidence: 99%

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Mixing in the Fermentation and Cell Culture Industries

Amanullah¹,

Buckland²,

Nienow

2003

Handbook of Industrial Mixing

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Section: -4 Mycelial Fermentationsmentioning

confidence: 90%

Section: -4 Mycelial Fermentationsmentioning

confidence: 99%

Mixing in the Fermentation and Cell Culture Industries

Amanullah¹,

Buckland²,

Nienow

2003

Handbook of Industrial Mixing

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“…Consequently, criteria such as mean power input, agitation rate, impeller tip speed, impeller-based Reynolds number or integrated shear factor are not appropriate as they represent average values derived from the geometric configuration of each system. Nevertheless, they have been widely used to correlate cell damage in a series of reports (Chen et al, 2003;Croughan et al, 1987;Kunas and Papoutsakis, 1990;Middler and Finn, 1966;Moreira et al, 1995;Sinskey et al, 1981;Ujcová et al, 1980). Unfortunately, while the concept proposed by GarciaBriones and Chalmers (1994) might appear appealing, at the most fundamental level it is impossible to implement at the current state of experimental and simulations capabilities.…”

Section: Introductionmentioning

confidence: 98%

Acute hydrodynamic forces and apoptosis: A complex question

Mollet

Godoy-Silva

Berdugo

et al. 2007

Biotech & Bioengineering

113

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A second generation flow contraction device was developed and modeled which allows cells to be subjected to well-defined hydrodynamic forces. Studies were conducted with this system on wild-type Chinese Hamster Ovary cells (CHO-K1) and a strain of CHO cells which expresses the human Bcl-2 triangle gene (CHO-bcl-2). In this study, the following questions were asked: (1) Does an acute hydrodynamic force induce apoptosis in wild-type CHO and CHO-bcl-2 cells? (2) Does the type of culture media make a difference with respect to the induction of apoptosis or necrosis? and (3) Does culture history affect induction of apoptosis or necrosis? The results obtained with this new flow contraction device and corresponding computer simulations are consistent with previously published studies with respect to the level of energy dissipation rate (EDR) required to create significant cell lysis. Second, while detectable relative to the control in the T-flask experiments, only a small fraction of the cells become apoptotic when exposed to a sub-lysis level of EDR (<10(8) W x m(-3)). Third, cells cultured in suspension with serum free media do not exhibit any higher or lower sensitivity (with respect to apoptosis) to various levels of EDR when compared to control cultures grown in T-flask and serum containing media; on the other hand, necrosis is significantly increased in experiments performed on suspended cells without serum. Fourth, the addition of the Bcl-2 gene product might slightly reduce the occurrence of apoptosis in T-flask culture; however, the baseline response is so low that the difference is insignificant.

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“…Although the inhibitory influences of intensive mixing on microorganisms used in submerged processes had been observed quite long ago [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], it seems that the term "turbohypobiosis" to denote the totality of these phenomena was used for the first time in 1986 [21]. The turbohypobiosis state is the interaction of a medium flow with living cells in local excess turbulent zones, which depends on the hydrodynamic conditions in the stirred tank reactor.…”

Section: Introductionmentioning

confidence: 99%

Excess turbulence as a cause of turbohypobiosis in cultivation of microorganisms

2007

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Abstract:The present review describes the influence of different types of mixing systems under excess turbulence conditions on microorganisms. Turbohypobiosis phenomena were described by applying a method for measurement of the kinetic energy of flow fluctuations based on the piezoeffect. It can be assumed that the shear stress effect (the state of turbohypobiosis) plays a role mainly when alternative mechanisms in cells cannot ensure a normal physiological state under stress conditions. Practically any system (inner construction of a bioreactor, culture and cultivation conditions, including mixing) requires its own optimisation to achieve the final goal, namely, the maximum product and/or biomass yields from substrate (Y P/S or/and Y X/S ), respectively. Data on the biotechnological performance of cultivation as well as power input, kinetic energy (e) of flow fluctuations, air consumption rate, rotational speed, tip speed, etc. do not correlate directly if the mixing systems (impellers-baffles) are dissimilar. Even the widely used specific power consumption cannot be relied upon for scaling up the cultivation performance using dissimilar mixing systems. A biochemical explanation for substrate and product transport via cell walls, carbon pathways, energy generation and utilisation, etc. furnishes insight into cellular interactions with turbulence of different origin for different types of microorganisms (single cells, mycelia forming cells, etc.

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Dependence of release of nucleotides from fungi on fermentor turbine speed

Cited by 58 publications

References 3 publications

Mixing in the Fermentation and Cell Culture Industries

Mixing in the Fermentation and Cell Culture Industries

Acute hydrodynamic forces and apoptosis: A complex question

Excess turbulence as a cause of turbohypobiosis in cultivation of microorganisms

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