scholarly journals Intensifying the Fermentation of Aspergillus oryzae in a Stirred Bioreactor Using Maxblend Impeller

2016 ◽  
Vol 10 (1) ◽  
pp. 88-109 ◽  
Author(s):  
Narges Ghobadi ◽  
Chiaki Ogino ◽  
Naoto Ohmura
Keyword(s):  
Growth Rate ◽  
Enzyme Activity ◽  
Power Consumption ◽  
Aspergillus Oryzae ◽  
Rushton Turbine ◽  
Stirred Bioreactor ◽  
Condition Effect ◽  
Batch Condition ◽  
Fermentation Parameters ◽  
Stirred Bioreactors

Background: The intensification of fermentation in stirred bioreactors is an attractive approach for commercial interests and industries that work with biochemical products. Alpha amylase is an enzymatic bio-products that is produced largely from Aspergillus oryzae. Using adaptable agitator can be an efficient way for stirred fermentation. Objective: This study, concentrated on enhancing the mixing process in order to intensify Aspergillus oryzae fermentation. A straight type of Maxblend® impeller was used as an agitator to investigate the incubation parameters compared with the use of a 6-blade double Rushton turbine. Method: Stirred fermentation was done in batch condition. Effect of flow pattern of mixing on fermentation parameters was investigated after each sampling. Results: The results showed that the Maxblend® significantly intensified both enzyme activity and growth rate at low and moderate rates of power consumption (P). The main reason for the decreases in the growth rate and the enzyme activity during agitation by the Rushton turbine at low and high Pv was the lack of oxygen and mycelial damage, respectively. Additionally, use of the Maxblend® significantly intensified the KLa at low and moderate rates of power consumption. Conclusion: Axial and uniform mixing by Maxblend® impeller was resulted in improving the fermentation characteristics and enzyme activity.

scholarly journals Optimization of the mixing in stirred bioreactors, 1. Comparative analysis of the mixing efficiency with different radial impellers for simulated broths

2007 ◽  
Vol 13 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Dan Cascaval ◽  
Anca-Irina Galaction ◽  
Elena Folescu
Keyword(s):  
Mixing Time ◽  
Ph Sensor ◽  
Mixing Efficiency ◽  
Energetic Efficiency ◽  
Rushton Turbine ◽  
Stirred Bioreactor ◽  
Mixing Intensity ◽  
Bulk Volume ◽  
Shear Effects ◽  
Stirred Bioreactors

Although radial impellers, especially the Rushton turbine, are widely used in stirred bioreactors, their applicability is limited by the high apparent viscosities of the broth. Beside the intensification of broth circulation, the energetic efficiency and the shear effects on biocatalysts must be taken into account to select the optimum impeller or impellers combination. In this context, the paper presents a comparative study on the efficiency of seven different radial impellers for simulated broth mixing in a stirred bioreactor. The analysis was made by means of the mixing time values obtained by vertically changing the position of the pH-sensor in the broths, in correlation with the energy consumption needed for a certain level of mixing time or for the uniform distribution of the mixing intensity into the bulk volume of the broths.

Hydrodynamics of Stirred Bioreactors

1998 ◽  
Vol 51 (1) ◽  
pp. 3-32 ◽  
Author(s):  
A. W. Nienow
Keyword(s):  
Energy Dissipation ◽  
Mixing Time ◽  
Scale Up ◽  
Axial Flow ◽  
High Viscosity ◽  
Flow Patterns ◽  
Rushton Turbine ◽  
Stirred Bioreactor ◽  
Power Characteristics ◽  
Stirred Bioreactors

This review of the hydrodynamics of stirred bioreactors begins with an introduction to the agitation problems of particular concern in such systems. This is followed by a brief review of some basic concepts in turbulence and rheology of relevance to bioreactors. Important aspects of single phase mixing in low viscosity, high viscosity and Theologically complex broths are then covered in some detail including flow patterns, power number versus Reynolds number plots (including the modification of the latter to allow for shear thinning broths), flow numbers, energy dissipation rates and flow close to impellers and between multiple impeller systems. From these basic principles, the problem of homogenization is then covered in depth because of its significance for bioreactor performance. Aeration concepts are then introduced and the behavior of traditional Rushton turbine impellers is then treated in detail, covering the flow patterns, aerated power characteristics, mixing time and scale-up considerations. The weaknesses of the Rushton turbine are then discussed which leads into a section describing how more modern impellers are able to improve on many of these, especially emphasising their ability to introduce more energy dissipation into the broth and handle more air before flooding, both of which enhance oxygen transfer. The improvement in bulk blending found with multiple axial flow agitators is brought out too. Finally, the retrofitting of fermenters originally containing Rushton turbines with these more modern impellers is discussed. In conclusion, it is clear that there have been substantial increases in the understanding of stirred bioreactor hydrodynamics. However, whilst further understanding will occur within the framework discussed here, the expectation must be that computational fluid dynamics will increase in importance in spite of the difficulty of handling complex rheology, multiphase systems and biological responses. This review article has 135 references.

scholarly journals Core–shell hydrogel microcapsules enable formation of human pluripotent stem cell spheroids and their cultivation in a stirred bioreactor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pouria Fattahi ◽  
Ali Rahimian ◽  
Michael Q. Slama ◽  
Kihak Gwon ◽  
Alan M. Gonzalez-Suarez ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Scale Up ◽  
Bioreactor Culture ◽  
Stirred Bioreactor ◽  
Cell Spheroids ◽  
Poly Ethylene ◽  
Aqueous Core ◽  
End Stage ◽  
Stirred Bioreactors

AbstractCellular therapies based on human pluripotent stem cells (hPSCs) offer considerable promise for treating numerous diseases including diabetes and end stage liver failure. Stem cell spheroids may be cultured in stirred bioreactors to scale up cell production to cell numbers relevant for use in humans. Despite significant progress in bioreactor culture of stem cells, areas for improvement remain. In this study, we demonstrate that microfluidic encapsulation of hPSCs and formation of spheroids. A co-axial droplet microfluidic device was used to fabricate 400 μm diameter capsules with a poly(ethylene glycol) hydrogel shell and an aqueous core. Spheroid formation was demonstrated for three hPSC lines to highlight broad utility of this encapsulation technology. In-capsule differentiation of stem cell spheroids into pancreatic β-cells in suspension culture was also demonstrated.

Effects of vessel baffling on the drawdown of floating solids

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Joanna Karcz ◽  
Beata Mackiewicz
Keyword(s):  
Experimental Data ◽  
Power Consumption ◽  
Strain Gauge ◽  
High Speed ◽  
Vessel Diameter ◽  
Rushton Turbine ◽  
Agitated Vessel ◽  
Dimensionless Equation ◽  
Inner Diameter ◽  
Floating Particles

AbstractThe effects of baffling of an agitated vessel on the production of floating particles suspension are presented in this paper. Critical agitator speed, needed for particles dispersion in a liquid agitated in a vessel of the inner diameter of 0.295 m, was determined. The just drawdown agitator speeds were defined analogously to the Zwietering criterion. Specific agitation energy was calculated from the power consumption experimental data obtained by means of the strain gauge method. The experiments were carried out for twelve configurations of the baffles differing in number, length and their arrangement in the vessels. The following high-speed impellers were used: up- and downpumping six blade pitched blade turbines, Rushton turbine, and propeller. The impeller was located in the vessel in the height equal to two-thirds or one-third of the vessel diameter from the bottom of the vessel. The results were described in the form of a dimensionless equation.

Effect of Baffle Length on Power Consumption in Turbulent Mixing Vessel with Rushton Turbine Impeller

2011 ◽  
Vol 37 (2) ◽  
pp. 147-149 ◽  
Author(s):  
Yoshihito Kato ◽  
Noboru Kamei ◽  
Yutaka Tada ◽  
Azusa Nakaoka ◽  
Yuichiro Nagatsu ◽  
...  
Keyword(s):  
Power Consumption ◽  
Turbulent Mixing ◽  
Rushton Turbine ◽  
Turbine Impeller

Scale process effect on the power consumption characteristics of a novel curved Rushton turbine within a reactor vessel

2021 ◽  
Vol 166 ◽  
pp. 109-120
Author(s):  
Ning Qiu ◽  
Peng Wang ◽  
Qiaorui Si ◽  
Willy E.K. Pettang ◽  
Shouqi Yuan
Keyword(s):  
Power Consumption ◽  
Reactor Vessel ◽  
Rushton Turbine

Improvement of the quality of soy sauce by reducing enzyme activity in Aspergillus oryzae

2019 ◽  
Vol 292 ◽  
pp. 81-89 ◽  
Author(s):  
Chengfang Ding ◽  
Meng Meng ◽  
Yuyang Jiang ◽  
Lihua Hou
Keyword(s):  
Enzyme Activity ◽  
Aspergillus Oryzae ◽  
Soy Sauce

scholarly journals The Effect of Experimental Conditions on Methane (95%)–Propane (5%) Hydrate Formation

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6710
Author(s):  
Sotirios Nik. Longinos ◽  
Mahmut Parlaktuna
Keyword(s):  
Power Consumption ◽  
Separation Factor ◽  
Induction Time ◽  
Hydrate Formation ◽  
Equilibrium Line ◽  
General View ◽  
Experimental Conditions ◽  
Rushton Turbine ◽  
Pitched Blade Turbine

In the present study, the effect of different kinds of impellers with different baffles or no baffle was investigated. Up-pumping pitched blade turbine (PBTU) and Rushton turbine (RT) were the two types of impellers tested. The reactor was equipped with different designs of baffles: full, half and surface baffles or no baffles. Single (PBTU or RT) and dual (PBTU/PBTU or RT/RT) use of impellers with full (FB), half (HB), surface (SB) and no baffle (NB) combinations formed two sets of 16 experiments. There was estimation of rate of hydrate formation, induction time, hydrate productivity, overall power consumption, split fraction and separation factor. In both single and dual impellers, the results showed that RT experiments are better compared to PBTU in rate of hydrate formation. The induction time is almost the same since we are deep in the equilibrium line while hydrate productivity values are higher in PBTU compared to RT experiments. As general view RT experiments consume more energy compared to PBTU experiments.

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