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Airlift bioreactors can provide an attractive alternative to stirred tanks, particularly for bioprocesses with gaseous reactants or products. Frequently, however, they are susceptible to being limited by gas-liquid mass transfer and by poor mixing of the liquid phase, particularly when they are operating at high cell densities. In this work we use...
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... The diameter of the draught tube to bioreactor diameter ratio (d/D) is 0.6 and the angle of the conical bottom is 251. The total volume of the reactor is 15 l with a working volume of 8-9 l. The remaining volume of the bioreactor is used as headspace volume, which is necessary to condense the vapour water and return it to the medium as shown in Fig. ...Context 2
... simulation process of the airlift bioreactor was carried out using COMSOL Multiphysics software (Version 4.1). The airlift bioreactor configuration that was used in the simulation is illustrated in Fig. 4. The present study used a range of microbubble diameters between 20 and 1000 mm with low gas (air) concentra- tion in water as a liquid phase. The temperature and pressure in this modelling were 298.15 K and 1 atm respectively. A laminar bubbly flow model interface was used for modelling of the two-fluid flow regimes (e.g. mixture from ...Citations
... Airlift bioreactor (Source: [35]). ...
Fermentation is derived from a Latin word fermentum, a process of chemical changes in an organic substrate by the action of microbial enzymes. The science of fermentation is called as zymology, and the first zymologist was Louis Pasteur. Study of fermentation is called as fermentation technology. Fermenter or bioreactor is the heart of fermentation technology where the whole study is involved. It is a container with biomechanical and biochemical environment that controls the transfer of oxygen, nutrient to the cells, and metabolic products from the cells. There are different types of fermenters like stirred tank fermenter, airlift fermenter, bubble column reactor, fluidized-bed reactor, packed bed reactor, and membrane bioreactor. There are different processes such as batch, continuous, and fed batch or semi-continuous. Secondary metabolites are produced either through submerged or solid-state fermentation process during the stationary phase of an organism. These metabolites are showing a rising demand in food, cosmetics, drugs, and other industries. The production of these metabolites can be improved by strain improvement through mutagenesis and r-DNA technologies. This chapter focuses on all these areas in detail.
... 17 Researchers have conducted extensive research to break up bubbles, increase gas-liquid interfacial area and residence time, and ultimately enhance gas holdup and volumetric mass transfer coefficient. 18 This paper categorizes optimization measures for loop reactor internal configuration into four categories. The first category focuses on controlling the initial bubble size, as smaller initial bubbles generally improve the volumetric mass transfer coefficient. ...
... Examples include the use of a 4-orifice nozzle, 19 novel membrane-tube sparger, 20 Venturi bubble generator, 21,22 and fluidic oscillator. 18,23 The second strategy involves interfering with rising bubbles to prevent aggregation and crushing large bubbles. This reduces bubble size, prolongs bubble residence time, and increases the volumetric mass transfer coefficient. ...
The multistage internal airlift loop reactor (MIALR) has shown promising application prospects in gas–liquid–solid reaction systems. However, traditional MIALRs have a global circulation with strong interstage liquid-phase exchange. This paper proposes a staggered multistage internal airlift loop reactor (SMIALR) that incorporates special guide elements to create a staggered flow. Both experiments and computational fluid dynamics-population balance model simulations were conducted to investigate the hydrodynamic performances of MIALR and SMIALR. The results demonstrate that SMIALR exhibits a local circulation at each stage. Bubbles have a longer residence time in SMIALR, resulting in a 28.35%–55.54% increase in gas holdup and a 7.27%–13.69% increase in volumetric mass transfer coefficient. The gas–liquid mass transfer coefficient of SMIALR was improved by increasing the gas–liquid interfacial area. Additionally, the radial distribution of solids was found to be more uniform. This study offers insights for optimizing MIALR and provides a theoretical foundation for the design and scale-up of SMIALR.
... Nanobubbles remain suspended in the water for longer periods of time without bursting (11). The DAF method uses microbubbles to increase the contaminant removal efficiency and flow velocity (13). The characteristics of microbubbles for flotation treatment are diameters ranging from 1 to 200 µm and an increased bubble inertial pressure with decreasing diameter without collapsing. ...
Context: This research developed a dissolved air flotation system using a Venturi tube to produce microbubbles. The Venturi tube replaces the saturation tank and the pressure-reducing valve of conventional systems. Method: The system has both suction and injection air inlets, regulates the recirculation flow of the liquid to the tank, and provides a high hydraulic load in a reduced size. Counting and measuring the microbubbles produced via digital image processing helps to characterize the system's performance. Results: The system with air suction produces smaller bubbles than that with air injection. A higher liquid recirculation pressure produces more bubbles and reduces their size in the case of air suction. Conclusions: In air injection, the change in flow rate influences the size of the microbubbles. Air injection and recirculation pressure do not influence the number of bubbles generated.
... Any liquid currents, even those induced by the injection of the bubble phase themselves, is likely to entrain 100µ diameter microbubbles so that they are suspended and circulating in the liquid phase. Transient simulations of microbubble injections show Zimmerman_06a_SC ACCEPTED MANUSCRIPT 17/02/2023 that the phase fraction of microbubbles suspended and circulating increases over time, but eventually plateaus as a steady level reflecting a much longer residence time (Al-Mashhadani et al. 2015). ...
... Scaling to large, industrial scale always results in imperfect mixing with slow mass transfer with impeller driven mixed vessels (Harnby et al., 1992). Hence, energy efficient, low power consumption, fluidic oscillation generated microbubbles have an important role in large scale operations, since they achieve high liquid mixing efficiencies (Al-Mashhadani et al., 2015). ...
... there is an internal baffle, such as in an airlift loop bioreactor, so that the riser region is actually well 14 mixed (Al-Mashhadani et al., 2015) This would explain why the Langmuir-like isotherm fitting works 15 so well, rather than a distributed system model such as deployed by Lemlich (1966). Similarly, Suzuki 16 et al. (1998) found that Langmuir-type isotherms described the fractionation of humic acid and crystal 17 violet in a bubble column very well. ...
Microbubbles are famed for their large surface area to volume ratio, with the promise of intensification of interfacial phenomena, highlighted by more rapid gas exchange. However, for bioprocessing, it has been recognized for many decades that surfactant-rich fermentation media hinders mass transfer and possibly other interfacial processes due to surfactant loading on the interface. This article focusses on the roles of microbubble size and bubble bank – dispersed microbubbles that are sufficiently small to be non-buoyant – in mediating other modes of interfacial transfer via collisions with microorganisms and self-assembled clusters of microorganisms and microbubbles. These provide a more direct route of mass transfer for product gases that can be released directly to the microbubble with ~104 faster diffusion rates than liquid mediated gas exchange. Furthermore, secreted external metabolites with amphoteric character are absorbed along the microbubble interface, providing a faster route for liquid solute transport than diffusion through the boundary layer. These mechanisms can be exploited by the emerging fields of symbiotic or microbiome engineering to design self-assembled artificial lichen dispersed structures that can serve as a scaffold for the selected constituents. Additionally, such designed scaffolds can be tuned, along with the controllable parameters of microbubble mediated flotation separations or hot microbubble stripping for simultaneous or in situ product removal. Staging the product removal thus has benefits of decreasing the inhibitory effect of secreted external metabolites on the microorganism that produced them. Evidence supporting these hypotheses are produced from reviewing the literature. In particular, recent work in co-cultures of yeast and microalgae in the presence of a dispersed bubble bank, as well as anaerobic digestion intensification with dispersed, seeded microbubbles, is presented to support these proposed artificial lichen clusters.
... Airlift bioreactors offer several advantages for large-scale bioprocesses, which are determined by the fluid dynamics and mass transfer characteristics [33]. The primary advantage of airlift bioreactors over other bioreactors is related to the homogeneous shear and stress forces distribution and the inexistence of focal points of energy dissipation throughout the reactor, which makes airlift bioreactors ideal for culturing shear sensitive cells, and also improves production on the bioprocess [33,34]. ...
... Our results showed an expression and purification of approximately 20 mg/L of culture (Figures 2 and 3), which was nearly 3 times higher than previously reported by Amaral et al. (2020) [36], and quite similar to those described by Liang et al. (2018) [41], who used an expression system based on E. coli and Drosophila cells. The 5-L airlift bioreactor used in this research allows automated control from the start to the end of the process, which improves tank circulation and oxygen transfer, as well as equalized shear forces in the reactor, with known, controlled, and reproducible cultivation conditions with greater homogeneity and productivity, contributing to a high yield and the expression of a high-quality protein [33,34,44]. ...
Citation: da Costa, H.H.M.; Bielavsky, M.; Orts, D.J.B.; Araujo, S.; Adriani, P.P.; Nogueira, J.S.; Astray, R.M.; Pandey, R.P.; Lancellotti, M.; Cunha-Junior, J.P.; et al. Production of Recombinant Zika Virus Envelope Protein by Airlift Bioreactor as a New Subunit Vaccine Platform. Int. J. Mol. Sci. 2023, 24, 13955. https://doi. Abstract: The Zika Virus (ZIKV) is an emerging arbovirus of great public health concern, particularly in the Americas after its last outbreak in 2015. There are still major challenges regarding disease control, and there is no ZIKV vaccine currently approved for human use. Among many different vaccine platforms currently under study, the recombinant envelope protein from Zika Virus (rEZIKV) constitutes an alternative option for vaccine development and has great potential for monitoring ZIKV infection and antibody response. This study describes a method to obtain a bioactive and functional rEZIKV using an E. coli expression system, with the aid of a 5-L airlift bioreactor and following an automated fast protein liquid chromatography (FPLC) protocol, capable of obtaining high yields of approximately 20 mg of recombinant protein per liter of bacterium cultures. The purified rEZIKV presented preserved antigenicity and immunogenicity. Our results show that the use of an airlift bioreactor for the production of rEZIKV is ideal for establishing protocols and further research on ZIKV vaccines bioprocess, representing a promising system for the production of a ZIKV envelope recombinant protein-based vaccine candidate.
... The medium of the vessels in these reactors is separated into two interconnected zones by a draught or a baffle tube (Kumar and Gunasundari, n.d.). When they operate at high cell densities, they are sensitive to being limited by gas-liquid mass transfer and poor liquid phase mixing (AL-Mashhadani et al. 2015). ...
... The medium of the vessels in these reactors is separated into two interconnected zones by a draught or a baffle tube (Kumar and Gunasundari, n.d.). When they operate at high cell densities, they are sensitive to being limited by gas-liquid mass transfer and poor liquid phase mixing (AL-Mashhadani et al. 2015). ...
Anthropogenic activity and the gradual enhancement in environmental contamination have been notably and recently developed. Bioremediation is a revolutionary innovation that can be used with existing physical and chemical treatment methods to handle various environmental contaminants, including using organisms to remove or neutralize pollutants. It provides the benefit of cleaning contaminated places utilizing natural processes and is less expensive since it does not require as much equipment, workforce, or energy as other cleanup procedures. The current chapter discusses various bioremediation types, techniques, and microorganisms.KeywordsBioremediationMicroorganismsMethods
EnvironmentEco-friendly
... The medium of the vessels in these reactors is separated into two interconnected zones by a draught or a baffle tube (Kumar and Gunasundari, n.d.). When they operate at high cell densities, they are sensitive to being limited by gas-liquid mass transfer and poor liquid phase mixing (AL-Mashhadani et al. 2015). ...
Industrial waste is an umbrella term that encompasses all undesirable by-products arising from manufacturing processes or derived from industrial operations. It comprises an array of solid, liquid, or gaseous wastes produced due to industrial activities which can be hazardous or non-hazardous and are modulated by distinct bodies of law and regulation. Environmental Protection Agency (EPA) controls all forms of waste at the federal level, providing guidelines for abidance and enforcing a sturdy fine for violation of the same. In recent times, considering the stringency in regulations and environmental concerns, industrial waste disposal and remediation adopt sustainably efficient solutions to reduce the toxicological effects and volume of the waste generated. Consequently, the high workload on the industrial sector is the high production of industrial effluents. Unfortunately, the primary objective of traditional treatment methods was to minimize the volume of industrial waste at a cheaper rate without considering sustainable alternatives and detrimental impacts on the environment. Understanding and establishing an equilibrium between cost-effectiveness and efficiency is the key to undertaking an adequate treatment method for industrial by-products. Environmental responsibility and stewardship are crucial for the sustainable protection of the planet against global trash without slowing down business. This chapter will discuss the various conventional methodologies adapted to treat waste from industries and industrial sectors.KeywordsWasteWastewaterIndustrial wastewaterBioremediationWastewater treatment
... We hope that the stem cell expansion optimization technology provided in this review will help to promote the clinical application of stem cells and their derivative products. bioreactor is operated at high cell density, its problems, such as gas-liquid mass transfer in the tank and poor liquid mixing, indicate that it is not fully suitable for large-scale production of stem cells [115]. In recent years, researchers have proposed the idea of using CFD as a major tool to design large airlift reactors for animal cell expansion to provide a priori estimates of the mass transfer and mixing performance of the reactors and to further study the effect of the internal structure of the reactors on cells without the need for expensive and time-consuming experiments [116][117][118]. ...
In recent years, great breakthroughs have been made in basic research and clinical applications of stem cells in regenerative medicine and other fields, which continue to inspire people to explore the field of stem cells. With nearly unlimited self-renewal ability, stem cells can generate at least one type of highly differentiated daughter cell, which provides broad development prospects for the treatment of human organ damage and other diseases. In the field of stem cell research, related technologies for inducing or isolating stem cells are relatively mature, and a variety of stable stem cell lines have been successfully constructed. To realize the full clinical application of stem cells as soon as possible, it is more and more important to further optimize each stage of stem cell research while conforming to Current Good Manufacture Practices (cGMP) standards. Here, we synthesized recent developments in stem cell research and focus on the introduction of xenogenicity in the preclinical research process and the remaining problems of various cell bioreactors. Our goal is to promote the development of technologies for xeno-free culture and clinical expansion of stem cells through in-depth discussion of current research. This review will provide new insight into stem cell research protocols and will contribute to the creation of efficient and stable stem cell expansion systems.
... Improving the mass transfer of gases between bubbles and liquid is the most popular goal at the moment [1,4]. Several previous studies have contributed to the development and realization of this task, including by controlling the size of bubbles, the nature and type of the diffuser used, or through the engineering development of the reactor as a whole [5][6][7][8]. Obtaining the longest possible contact time between the liquid phase and gas phase with a satisfactory interfacial area represents the backbone in achieving this improvement for the transfer of the desired material between the two-phase [4,9]. ...
Reactors or bioreactors used in industries or for the growth and reproduction of microorganisms face several
challenges. The poor mass transfer and heat transfer with the generation of dead zones are the most important of these challenges.
The current research is a serious attempt to improve the mixing efficiency in these reactors to provide suitable conditions for
reactions. Numerical modelling of liquid hydrodynamics was developed for optimization of the geometry of inner draft-tube in an
airlift bioreactor operating for chemical or biochemical applications. The performance of the mixing was based on the velocity of
liquid phase in riser region. Effect of height, radius, and position of draft tube on the recirculation of liquid in rizer region was
investigated in current study. The study showed that reducing the diameter of the inner tube has a positive effect on the mixing
efficiency, provided that it is not less than the diameter of the diffuser. While increasing the diameter reduces the mixing
efficiency, even if the height of the pipe or its location in relation to the base of the reactor increases. The study concluded that
the internal engineering parts of the reactor have an effect on the dynamic movement of the fluid.
