Turbulent breakage of filamentous microorganisms in submerged culture in mechanically stirred bioreactors

Shamlou, P. Ayazi; Makagiansar, Helena Yusuf; Ison, A. P.; Lilly, M. D.; Thomas, C. R.

doi:10.1016/0009-2509(94)e0079-6

Cited by 85 publications

(42 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Summarising the results of a number of studies [1,[58][59][60][61][62][63][64], plant and animal cells were found to be less resistant than the hyphae of mycelial cultures, followed by yeast, while bacteria appeared to be the least resistant. This can be very easily explained by the cell membrane structure (its mechanical strength) as well as the dimensions of cells (i.e.…”

Section: Figmentioning

confidence: 99%

“…The studies carried out by different authors are not comparable quantitatively, because different authors describe the hydrodynamic situation with different criteria. Thus some authors [58,63] measured shear velocity, while the others [59] focused on shear stress, maximum [60] and mean [1,48,56,65] dissipated energy, medium and gas flows velocity [63], blade tip speed [58] and stirrer rotational speed [1,61,62,64]. Besides, different constructions of the stirrer and apparatus were used.…”

Section: Figmentioning

confidence: 99%

“…Besides, different constructions of the stirrer and apparatus were used. Still, some common regularities follow from these studies, namely, the amount of the damaged cells depends not only on the average value of the input power but also on the stirrer design [1,64]], the time of the influence of hydrodynamic stress [61,64], the concentration, dimensions and shape of insoluble substrate particles [1,61].…”

Section: Figmentioning

confidence: 99%

See 2 more Smart Citations

Excess turbulence as a cause of turbohypobiosis in cultivation of microorganisms

2007

View full text Add to dashboard Cite

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.

show abstract

Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Excess turbulence as a cause of turbohypobiosis in cultivation of microorganisms

2007

View full text Add to dashboard Cite

show abstract

“…Hydrodynamic forces, collisions between particles, collisions between particles and the wall of the tank, or between particle and stirrer device can all cause the breakup of flocs. If the density difference between particle and fluid is low, particle disruption via collisions is relatively insignificant (Ayazi Shamlou et al, 1994a). In case of yeast flocculation the effective density is very low, so only hydrodynamic forces will need to be considered.…”

Section: Model Developmentmentioning

confidence: 99%

Modeling brewers' yeast flocculation

Hamersveld

Lans

Caulet³

et al. 1998

Biotechnol. Bioeng.

View full text Add to dashboard Cite

“…15,19,25,26 Since protein secretion has been shown to be predominantly associated with the apical regions, 27,28 any factor which impacts upon morphological form might have a signi®cant effect upon protein secretion in such organisms. This effect could be mediated indirectly, via an overall change in growth of the fungus, or, rather more directly, via change in the frequency of tip formation per unit hyphal length (ie an alteration in the relative proportion of cell mass devoted to protein synthesis).…”

Section: ±20mentioning

confidence: 99%

Secretion of heterologous and native proteins, growth and morphology in batch cultures of Aspergillus niger B1‐D at varying agitation rates

Wongwicharn

Harvey

McNeil

1999

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

The in¯uence of bioreactor operational conditions on the micromorphology of batch cultures of Aspergillus niger B1-D, containing a hen egg white lysozome (HEWL) marker protein, was examined using computerised image analysis. Signi®cant differences in micromorphology were observed with increased stirrer speed, with shorter organisms with shorter hyphal elements occurring as agitation speed increased, even though mean tip numbers were similar. This may explain the observed increase in the total extracellular protein, since the ratio of synthetic (tip) to non-synthetic zones became increasingly favourable. HEWL concentrations fell above 500 rpm, probably due to the effects of DOT (dissolved oxygen tension) on the glucoamylase HEWL fusion. HEWL was susceptible to proteolytic degradation, by native proteases, during the autolytic phase. Such insights may indicate why a gene from one mould expressed in a close relative can give production levels equivalent to levels of native enzymes, while secretion of a gene from a`distant' source, eg a higher eukaryotic gene, occurs at much lower levels.

show abstract

Turbulent breakage of filamentous microorganisms in submerged culture in mechanically stirred bioreactors

Cited by 85 publications

References 43 publications

Excess turbulence as a cause of turbohypobiosis in cultivation of microorganisms

Excess turbulence as a cause of turbohypobiosis in cultivation of microorganisms

Modeling brewers' yeast flocculation

Secretion of heterologous and native proteins, growth and morphology in batch cultures of Aspergillus niger B1‐D at varying agitation rates

Contact Info

Product

Resources

About