Impact of rheology on the mass transfer coefficient during the growth phase of Trichoderma reesei in stirred bioreactors

Gabelle, Jean-Christophe; Jourdier, Etienne; Licht, R.B.; Chaabane, Fadhel Ben; Hénaut, I.; Morchain, Jérôme; Augier, Frédéric

doi:10.1016/j.ces.2012.03.053

Cited by 72 publications

(37 citation statements)

References 51 publications

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“…Hence, during such cultivations also the liquid film thickness will increase as a result of increasing viscosity. For stirred tanks with dedicated impeller design and at high power input, maximum viscosities of up to 1,000 mPa s have been reported in literature (Bhargava et al, ; Gabelle et al, ; Johansen et al, ; Neves et al, ; Peña et al, ). Table shows microorganisms that increased the viscosity of their culture broth during cultivation in shake flasks.…”

Section: Resultsmentioning

confidence: 96%

“…For the stirred tank reactor, the OTR max between 50 and 80 mPa s is only approximately 5% of the initial OTR max at 1 mPa s. At that viscosity range the OTR max in shake flasks does not markedly fall below the initial value. At an even higher viscosity of 225 mPa s, which is not untypical for a number of industrial relevant fermentations (Bhargava et al, 2005;Gabelle et al, 2012;Johansen et al, 1998;Neves et al, 2000;Peña et al, 2000), the OTR max in shake flasks, is still 60% of the OTR max at 1 mPa s (Fig. 7).…”

Section: Experiments With C Glutamicum In Culture Mediummentioning

confidence: 98%

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Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity

Giese

Azizan

Kümmel

et al. 2013

Biotech & Bioengineering

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In biotechnological screening and production, oxygen supply is a crucial parameter. Even though oxygen transfer is well documented for viscous cultivations in stirred tanks, little is known about the gas/liquid oxygen transfer in shake flask cultures that become increasingly viscous during cultivation. Especially the oxygen transfer into the liquid film, adhering on the shake flask wall, has not yet been described for such cultivations. In this study, the oxygen transfer of chemical and microbial model experiments was measured and the suitability of the widely applied film theory of Higbie was studied. With numerical simulations of Fick's law of diffusion, it was demonstrated that Higbie's film theory does not apply for cultivations which occur at viscosities up to 10 mPa s. For the first time, it was experimentally shown that the maximum oxygen transfer capacity OTRmax increases in shake flasks when viscosity is increased from 1 to 10 mPa s, leading to an improved oxygen supply for microorganisms. Additionally, the OTRmax does not significantly undermatch the OTRmax at waterlike viscosities, even at elevated viscosities of up to 80 mPa s. In this range, a shake flask is a somehow self-regulating system with respect to oxygen supply. This is in contrary to stirred tanks, where the oxygen supply is steadily reduced to only 5% at 80 mPa s. Since, the liquid film formation at shake flask walls inherently promotes the oxygen supply at moderate and at elevated viscosities, these results have significant implications for scale-up.

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Section: Resultsmentioning

confidence: 96%

Section: Experiments With C Glutamicum In Culture Mediummentioning

confidence: 98%

Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity

Giese

Azizan

Kümmel

et al. 2013

Biotech & Bioengineering

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“…During the fermentation process, the rheology of the medium evolves from viscous to highly non‐Newtonian behavior. The increase of apparent viscosity of the fluid tends to decrease mass‐transfer performance . Consequently, to maintain the oxygen level in the reactor, aeration and agitation have to be increased.…”

Section: Introductionmentioning

confidence: 99%

Experimental determination of the shear rate in a stirred tank with a non‐newtonian fluid: Carbopol

et al. 2012

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in Wiley Online Library (wileyonlinelibrary.com).The local shear rate generated in a cylindrical tank equipped with a Rushton turbine was investigated using particle image velocimetry in a shear-thinning fluid (Carbopol). This non-Newtonian fluid was used in an attempt to mimic fermentation broths. Three Reynolds numbers corresponding to the transition regime were investigated. The hydrodynamics is analyzed, and the velocity field is decomposed by proper orthogonal decomposition into mean flow, organized motion, and turbulence. Then, the contributions of each flow structure to the total dissipation of kinetic energy are presented. The spatial heterogeneity of shear rate is discussed and a new expression is proposed for shear rate. This work shows that the local shear rate is highly heterogeneous in a tank. Future works will need to focus on other types of stirrer and investigate the effect of scaling up reactors on the shear rate heterogeneity.

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“…Trichoderma reesei (Bhat 2000) such degradation capabilities were the focus of studies evaluating the biotechnological potential of other cellulase-producing Coniochaeta species (Lopez et al 2007). However, the ability of C. pulveracea to switch to a yeast-like growth may impact on its rheological properties, an aspect that is important in reactor design for cellulolytic filamentous industrial fungi (Gabelle et al 2012). The conditions needed for C. pulveracea to switch to microcyclic conidiation, however, are still unknown.…”

Section: Introductionmentioning

confidence: 99%

The microcyclic conidial stage of Coniochaeta pulveracea and its effect on selected biological interactions

et al. 2015

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Coniochaeta pulveracea is a dimorphic lignicolous fungus that has mostly been isolated from decaying wood. However, relatively little work was conducted on the conditions for the dimorphic switch or the biological interactions of the fungus in its yeast-like microcyclic growth phase. Therefore, in this study, the microcyclic conidiation of C. pulveracea strains and representatives of the closely related species, Coniochaeta boothii and Coniochaeta subcorticalis, was studied under different environmental conditions. The strains were found to exhibit hyphal growth on solid substrates and underwent a dimorphic switch to produce microcycle conidiation upon transfer to a liquid medium which differed in physico-chemical composition compared to the original solid medium. Factors that were found to contribute to this dimorphic switch were temperature, pH and the presence of complex nitrogen sources such as casamino acids and peptone in the medium. However, C. pulveracea showed intraspecific differences with regard to its response to changes in the physico-chemical environment. The interactions of microcyclic Coniochaeta strains with selected yeasts, such as representatives of Meyerozyma guilliermondii and Cryptococcus neoformans, were subsequently studied in complex liquid media and it was found that, depending on medium composition, the microcyclic Coniochaeta exerted different effects on the different yeasts strains. In some co-cultures, a positive effect on yeast growth was observed, whilst in other cases microcyclic Coniochaeta inhibited yeast growth.

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Impact of rheology on the mass transfer coefficient during the growth phase of Trichoderma reesei in stirred bioreactors

Cited by 72 publications

References 51 publications

Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity

Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity

Experimental determination of the shear rate in a stirred tank with a non‐newtonian fluid: Carbopol

The microcyclic conidial stage of Coniochaeta pulveracea and its effect on selected biological interactions

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