Bioreactors: Control, Optimization and Applications

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.5	5.3	2011	18.4 Days	CHF 2400	Submit
Bioengineering bioengineering	3.8	4.0	2014	16.4 Days	CHF 2700	Submit
Fermentation fermentation	3.3	3.8	2015	15.4 Days	CHF 2100	Submit
Processes processes	2.8	5.1	2013	14.9 Days	CHF 2400	Submit
Water water	3.0	5.8	2009	17.5 Days	CHF 2600	Submit

20 pages, 7370 KiB

Open AccessArticle

Output Feedback Regulation via Sinusoidal Control with Application to Semi-Continuous Bio/Chemical Reactors

by Ricardo Aguilar-López, Ricardo Femat and Juan L. Mata-Machuca

Processes 2025, 13(3), 891; https://doi.org/10.3390/pr13030891 - 18 Mar 2025

Viewed by 197

This work proposes a nonlinear control strategy, an output feedback control based on a sinusoidal control approach for output regulation purposes with application to semi-continuous (fed-batch) bio/chemical processes. A key feature of the proposed control scheme is its auto-stop property, which ensures that [...] Read more.

This work proposes a nonlinear control strategy, an output feedback control based on a sinusoidal control approach for output regulation purposes with application to semi-continuous (fed-batch) bio/chemical processes. A key feature of the proposed control scheme is its auto-stop property, which ensures that the required set points are reached while automatically ceasing control input. This is particularly advantageous in fed-batch reactors, where exceeding the maximum operative volume is a common concern; additionally, the proposed controller can be bounded by only selecting the amplitude of the sine function. The closed-loop stability of the designed auto-stop control law is analyzed via the Lyapunov–Krazovzkii framework, which allows us to claim that the closed-loop dynamic operation of the corresponding processes is stable. The proposed controller is applied to two typical examples of semi-continuous bio/chemical reactors for regulation purposes, which aim to increase the reactors’ productivity. In addition, a comparison with a well-tuned internal model control proportional–integral (IMC PI) controller is performed. To show the performance of the control schemes, numerical experiments were carried out to show the controllers’ performance under different and realistic operation conditions. Here, for the bioreactor example, the performance index does not reach a steady state, but the gap between the IMC PI controller and the proposed one is around 100, 200, and 250 units for the different set points, which is in favor of the proposed controller. Regarding the chemical reactor, the performance index of the corresponding gap between the steady-state values of the performance index is also in favor of the proposed control law. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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21 pages, 5270 KiB

Open AccessArticle

Mimicking Marine Conditions to Improve Prodigiosin Yields in Bioreactor

by Ricardo F. S. Pereira and Carla C. C. R. de Carvalho

Processes 2024, 12(9), 1794; https://doi.org/10.3390/pr12091794 - 23 Aug 2024

Cited by 2 | Viewed by 1536

Abstract

Prodigiosin is a red bacterial pigment with great potential as a natural dye and drug precursor, while presenting several pharmacological properties, including antimicrobial and anticancer activities. Its commercialization for biomedical applications, however, remains scarce. The major limitations are related to the lack of [...] Read more.

Prodigiosin is a red bacterial pigment with great potential as a natural dye and drug precursor, while presenting several pharmacological properties, including antimicrobial and anticancer activities. Its commercialization for biomedical applications, however, remains scarce. The major limitations are related to the lack of efficient bioprocesses and scaling up from laboratory to production. In the present work, the upstream process for prodigiosin production was developed using a marine Serratia rubidaea isolated from a sample collected near a shallow-water hydrothermal vent. The yield of product per biomass was found to be influenced by the cell concentration in the inoculum. The system was scaled up to 2 L stirred tank reactors with two different vessel geometries. It was shown that the vessel geometry and a cascade control mode for regulating the dissolved oxygen concentration influenced the volumetric oxygen mass transfer coefficient (k_La) and thus prodigiosin production. To improve product yields, strategies to mimic the aeration conditions found at the sampling site were tested. When the inoculum was grown for 5 h at 200 rpm and for 19 h at 25 rpm, which significantly decreased the oxygen available, the cells produced 588.2 mg_product/g_biomass, corresponding to a production of 1066.2 mg of prodigiosin in 24 h and a productivity of 36.1 mg_product/(L.h). This is a 3.7-fold increase in prodigiosin yield and a 4.5-fold increase in productivity in relation to when no particular strategy was promoted. Additionally, it was shown that lipid analysis and flow cytometry may be used as reliable at-line analytical tools, allowing the monitoring of cell condition and prodigiosin production during fermentation. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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16 pages, 4490 KiB

Open AccessArticle

Design and Validation of a PLC-Controlled Morbidostat for Investigating Bacterial Drug Resistance

by Adrián Pedreira, José A. Vázquez, Andrey Romanenko and Míriam R. García

Bioengineering 2024, 11(8), 815; https://doi.org/10.3390/bioengineering11080815 - 10 Aug 2024

Viewed by 1473

Abstract

During adaptive laboratory evolution experiments, any unexpected interruption in data monitoring or control could lead to the loss of valuable experimental data and compromise the integrity of the entire experiment. Most homemade mini-bioreactors are built employing microcontrollers such as Arduino. Although affordable, these [...] Read more.

During adaptive laboratory evolution experiments, any unexpected interruption in data monitoring or control could lead to the loss of valuable experimental data and compromise the integrity of the entire experiment. Most homemade mini-bioreactors are built employing microcontrollers such as Arduino. Although affordable, these platforms lack the robustness of the programmable logic controller (PLC), which enhances the safety and robustness of the control process. Here, we describe the design and validation of a PLC-controlled morbidostat, an innovative automated continuous-culture mini-bioreactor specifically created to study the evolutionary pathways to drug resistance in microorganisms. This morbidostat includes several improvements, both at the hardware and software level, for better online monitoring and a more robust operation. The device was validated employing Escherichia coli, exploring its adaptive evolution in the presence of didecyldimethylammonium chloride (DDAC), a quaternary ammonium compound widely used for its antimicrobial properties. E. coli was subjected to increasing concentrations of DDAC over 3 days. Our results demonstrated a significant increase in DDAC susceptibility, with evolved populations exhibiting substantial changes in their growth after exposure. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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12 pages, 2556 KiB

Open AccessCommunication

A Bioreactor for Celullarised Membrane Culture and Delivery under Sterile Conditions

by Ainitze Gereka, Uzuri Urtaza, Pablo Larreategi, Felipe Prosper, Enrique José Andreu and Ane Miren Zaldua

Bioengineering 2024, 11(8), 785; https://doi.org/10.3390/bioengineering11080785 - 2 Aug 2024

Viewed by 1203

Abstract

A novel, user-friendly bioreactor for the cultivation of cellularised membranes for tissue engineering has been successfully designed, manufactured, and validated. This bioreactor features a culture vessel and a cover, the latter equipped with one or more sidewalls to ensure airtightness in two distinct [...] Read more.

A novel, user-friendly bioreactor for the cultivation of cellularised membranes for tissue engineering has been successfully designed, manufactured, and validated. This bioreactor features a culture vessel and a cover, the latter equipped with one or more sidewalls to ensure airtightness in two distinct zones, thereby maintaining sterile conditions. The cover, designed to integrate seamlessly with the culture vessel, includes several ports compatible with commercial connectors. This design allows the introduction of cells and culture medium without requiring the opening of the cover, thus preserving sterility. Additionally, the cover is equipped with flanges that effectively press the membrane against the bottom surface of the culture vessel, preventing it from shrinking or shifting. This ensures that cells can properly adhere to the membrane and proliferate. Manufactured under Good Manufacturing Practice (GMP) conditions, the bioreactor supports cultivation in optimal aseptic environments, thereby preventing external contamination. This feature is critical for the safe transportation of cultivated tissue to clinical settings. Validation tests have confirmed the bioreactor’s excellent performance, endorsing its suitability for intended applications in tissue engineering. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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31 pages, 6930 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Energy-Efficient Production of Microchloropsis salina Biomass with High CO₂ Fixation Yield in Open Thin-Layer Cascade Photobioreactors

by Ayşe Koruyucu, Torben Schädler, Amelie Gniffke, Konrad Mundt, Susann Krippendorf, Peter Urban, Karlis Blums, Billy Halim, Thomas Brück and Dirk Weuster-Botz

Processes 2024, 12(7), 1303; https://doi.org/10.3390/pr12071303 - 23 Jun 2024

Cited by 1 | Viewed by 1843

Abstract

Lipid production using microalgae is challenging for producing low-value-added products. Harnessing microalgae for their fast and efficient CO₂ fixation capabilities may be more reasonable since algal biomass can be utilized as a precursor for various products in a biorefinery approach. This study [...] Read more.

Lipid production using microalgae is challenging for producing low-value-added products. Harnessing microalgae for their fast and efficient CO₂ fixation capabilities may be more reasonable since algal biomass can be utilized as a precursor for various products in a biorefinery approach. This study aimed to optimize the productivity and efficiency of Microchloropsis salina biomass production in open thin-layer cascade (TLC) photobioreactors under physical simulation of suitable outdoor climate conditions, using an artificial seawater medium. Continuous operation proved to be the most suitable operating mode, allowing an average daily areal productivity of up to 27 g m⁻² d⁻¹ and CO₂ fixation efficiency of up to 100%. Process transfer from 8 m² to 50 m² TLC photobioreactors was demonstrated, but with reduced daily areal productivity of 21 g m⁻² d⁻¹ and a reduced CO₂ fixation efficiency, most probably due to increased temperatures at midday above 35 °C. An automated overnight switch-off of the circulation pumps was implemented successfully, reducing energy and freshwater requirements by ~40%. The ideal conditions for continuous production were determined to be a dilution rate of 0.150–0.225 d⁻¹, pH of 8.5, and total alkalinity of 200–400 ppm, facilitating efficient pilot-scale production of microalgal biomass in TLC photobioreactors. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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11 pages, 2152 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improving Microalgae Feasibility Cultivation: Preliminary Results on Exhausted Medium Reuse Strategy

by Luigi Marra, Elena Aurino, Francesca Raganati, Antonino Pollio and Antonio Marzocchella

Processes 2024, 12(5), 1029; https://doi.org/10.3390/pr12051029 - 19 May 2024

Cited by 1 | Viewed by 1506

Abstract

Although microalgae exploitation is very promising, process sustainability is undermined by biomass production and harvesting. Among the various bottlenecks of the production process, particular attention should be paid to the water footprint. Indeed, a huge volume of water is required in microalgae production. [...] Read more.

Although microalgae exploitation is very promising, process sustainability is undermined by biomass production and harvesting. Among the various bottlenecks of the production process, particular attention should be paid to the water footprint. Indeed, a huge volume of water is required in microalgae production. Water reuse can support both the water footprint and medium cost reduction, saving water and unconverted substrates. The present study reports preliminary results regarding the utilization of a water reuse strategy for two Chlorophyta microalgae under batch conditions. Growth parameters and chlorophyll content are monitored and the optimal amount of reused medium is assessed. The results show that 70% of the medium can be reused with no loss of specific growth rate and chlorophyll fraction for Pseudococcomyxa simplex in three consecutive batch cultivations. By contrast, a significant decline in Chlorella vulgaris growth was observed after the first cultivation in reused medium, across all tested conditions. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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16 pages, 1983 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Scaling Fed-Batch and Perfusion Antibody Production Processes in Geometrically Dissimilar Stirred Bioreactors

by Vivian Ott, Jan Ott, Dieter Eibl and Regine Eibl

Processes 2024, 12(4), 806; https://doi.org/10.3390/pr12040806 - 17 Apr 2024

Cited by 1 | Viewed by 5267

Abstract

Modern production processes for biopharmaceuticals often work with very high cell densities. Moreover, there is a trend towards moving from fed-batch to continuous perfusion processes; a development that is influencing the requirements for bioreactor design and process control. In this study, the transfer [...] Read more.

Modern production processes for biopharmaceuticals often work with very high cell densities. Moreover, there is a trend towards moving from fed-batch to continuous perfusion processes; a development that is influencing the requirements for bioreactor design and process control. In this study, the transfer of fed-batch and perfusion experiments between different cylindrical stirred lab-scale bioreactors and Thermo Scientific’s^TM (Waltham, MA, USA) cubical HyPerforma^TM DynaDrive^TM Single-Use Bioreactor was investigated. Different scaling parameters were used, which were selected based on the requirements of the respective processes. Peak cell densities of up to 49 × 10⁶ cells mL⁻¹ and antibody titers of up to 5.2 g L⁻¹ were achieved in 15- to 16-day fed-batch experiments. In 50-day perfusion cultivations, a viable cell volume of >100 mm³ mL⁻¹ was maintained and more than 1 g L⁻¹ d⁻¹ of antibodies were harvested. The perfusion processes were automated with both cell bleed control and glucose concentration control. Cell retention was performed using Repligen’s (Waltham, MA, USA) XCell^® ATF perfusion systems and single-use devices. In summary, approaches for successfully scaling highly productive fed-batch and perfusion processes between geometrically dissimilar lab and pilot scale bioreactors were demonstrated. The advantages of perfusion in comparison to fed-batch processes were also observed. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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13 pages, 1201 KiB

Open AccessArticle

Improved Performance of Sulfur-Driven Autotrophic Denitrification Process by Regulating Sulfur-Based Electron Donors

by Jiang Xu, Zhikun Lu, Yifeng Xu, Chuanzhou Liang and Lai Peng

Water 2024, 16(5), 730; https://doi.org/10.3390/w16050730 - 29 Feb 2024

Cited by 2 | Viewed by 2145

Abstract

Sulfur-driven autotrophic denitrification (SADN) has demonstrated efficacy in nitrate (NO₃⁻) removal from the aquatic environment. However, the insolubility of elemental sulfur (S⁰) (maximum 5 μg/L at 25 °C) limited the NO₃⁻ removal rate. In this study, [...] Read more.

Sulfur-driven autotrophic denitrification (SADN) has demonstrated efficacy in nitrate (NO₃⁻) removal from the aquatic environment. However, the insolubility of elemental sulfur (S⁰) (maximum 5 μg/L at 25 °C) limited the NO₃⁻ removal rate. In this study, we investigated the performance of a laboratory-scale S⁰-packed bed reactor (S⁰-PBR) under various volumetric NO₃⁻ loading rates. By filling with smaller S⁰ particles (0.5–1 mm) and introducing chemical sulfide (30–50 mg S²⁻-S/L), a high NO₃⁻ removal rate (1.44 kg NO₃⁻-N/(m³·d)) was achieved, which was substantially higher than previously reported values in SADN systems. The analysis of the average specific NO₃⁻ removal rates and the half-order kinetic constants jointly confirmed that the denitrification performance was significantly enhanced by decreasing the S⁰ particle sizes from 10–12 mm to 1–2 mm. The smaller S⁰ particles with a larger specific surface area improved the mass-transfer efficiency. Dosing chemical S²⁻ (20 mg S²⁻-S/L) to trigger the abiotic polysulfuration process increased the specific NO₃⁻ removal rate from 0.366 to 0.557 g NO₃⁻-N/g VSS/h and decreased the portion of removed NO₃⁻-N in the form of nitrous oxide (N₂O-N) from 1.6% to 0.7% compared to the S²⁻-free group. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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15 pages, 8430 KiB

Open AccessArticle

Process Intensification in Human Pluripotent Stem Cell Expansion with Microcarriers

by Misha Alexander Teale, Samuel Lukas Schneider, Dieter Eibl and Regine Eibl

Processes 2024, 12(3), 426; https://doi.org/10.3390/pr12030426 - 20 Feb 2024

Cited by 2 | Viewed by 2674

Abstract

Given the demands human induced pluripotent stem cell (hiPSC)-based therapeutics place on manufacturing, process intensification strategies which rapidly ensure the desired cell quality and quantity should be considered. Within the context of antibody and vaccine manufacturing, one-step inoculation has emerged as an effective [...] Read more.

Given the demands human induced pluripotent stem cell (hiPSC)-based therapeutics place on manufacturing, process intensification strategies which rapidly ensure the desired cell quality and quantity should be considered. Within the context of antibody and vaccine manufacturing, one-step inoculation has emerged as an effective strategy for intensifying the upstream process. This study therefore evaluated whether this approach could be applied to the expansion of hiPSCs in flasks under static and in microcarrier-operated stirred bioreactors under dynamic conditions. Our findings demonstrated that high density working cell banks containing hiPSCs at concentrations of up to 100 × 10⁶ cells mL⁻¹ in CryoStor^® CS10 did not impair cell growth and quality upon thawing. Furthermore, while cell distribution, growth, and viability were comparable to routinely passaged hiPSCs, those subjected to one-step inoculation and expansion on microcarriers under stirred conditions were characterized by improved attachment efficiency (≈50%) following the first day of cultivation. Accordingly, the process development outlined in this study establishes the foundation for the implementation of this intensified approach at L-scale. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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23 pages, 2508 KiB

Open AccessReview

A Review of AI-Driven Control Strategies in the Activated Sludge Process with Emphasis on Aeration Control

by Celestine Monday, Mohamed S. Zaghloul, Diwakar Krishnamurthy and Gopal Achari

Water 2024, 16(2), 305; https://doi.org/10.3390/w16020305 - 16 Jan 2024

Cited by 10 | Viewed by 4578

Abstract

Recent concern over energy use in wastewater treatment plants (WWTPs) has spurred research on enhancing efficiency and identifying energy-saving technologies. Treating one cubic meter of wastewater consumes at least 0.18 kWh of electricity. About 50% of the energy consumed during this process is [...] Read more.

Recent concern over energy use in wastewater treatment plants (WWTPs) has spurred research on enhancing efficiency and identifying energy-saving technologies. Treating one cubic meter of wastewater consumes at least 0.18 kWh of electricity. About 50% of the energy consumed during this process is attributed to aeration, which varies based on treatment quality and facility size. To harness energy savings in WWTPs, the transition from traditional controls to artificial intelligence (AI)-based strategies has been observed. Research in this area has demonstrated significant improvements to the efficiency of wastewater treatment. This contribution offers an extensive review of the literature from the past decade. It aims to contribute to the ongoing discourse on improving the efficiency and the sustainability of WWTPs. It covers conventional and advanced control strategies, with a particular emphasis on AI-based control utilizing algorithms such as neural networks and fuzzy logic. The review includes four key areas of wastewater treatment AI research as follows: parameter forecasting, performance analysis, modeling development, and process optimization. It also points out potential disadvantages of using AI controls in WWTPs as well as research gaps such as the limited translation of AI strategies from research to real-world implementation and the challenges associated with implementing AI models outside of simulation environments. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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12 pages, 1925 KiB

Open AccessArticle

Maximizing Bio-Hydrogen and Energy Yields Obtained in a Self-Fermented Anaerobic Bioreactor by Screening of Different Sewage Sludge Pretreatment Methods

by Alaa A. El-kebeer, Usama F. Mahmoud, Sayed Ismail, Abu Abbas E. Jalal, Przemysław Kowal, Hussein E. Al-Hazmi and Gamal K. Hassan

Processes 2024, 12(1), 118; https://doi.org/10.3390/pr12010118 - 2 Jan 2024

Cited by 5 | Viewed by 2256

Abstract

Egypt faces significant challenges in managing its sewage sludge generated in large quantities from wastewater treatment plants. This study investigates the feasibility of utilizing sewage sludge as a renewable resource for hydrogen production through anaerobic digestion at the 100 L bioreactor level. Hydrogen [...] Read more.

Egypt faces significant challenges in managing its sewage sludge generated in large quantities from wastewater treatment plants. This study investigates the feasibility of utilizing sewage sludge as a renewable resource for hydrogen production through anaerobic digestion at the 100 L bioreactor level. Hydrogen is considered a promising alternative energy source due to its high energy content and environmental benefits. To optimize the microbial degradation process and maximize hydrogen production from sewage sludge, a specialized pretreatment is necessary. Various pretreatment methods have been applied to the sewage sludge, individually and in combination, to study the bio-hydrogen production from sewage sludge. The four methods of treatment were studied in batch assays as a pilot scale. Thermal pretreatment of sewage sludge significantly increases bio-hydrogen production yield compared to other sewage sludge pretreatment methods, producing the highest H₂ yield (6.48 LH₂/g VS). In general, the hydrogen yield of any type of pretreated inoculum was significantly higher than the untreated inoculum. At the same time, alkaline pretreatment improved the hydrogen yield (1.04 LH₂/g VS) more than acid pretreatment (0.74 LH₂/g VS), while the hydrogen yield for the combination of pretreatments (shock alkali pretreatment) was higher than both (1.73 LH₂/g VS), On the other hand, untreated sewage sludge (control) had almost no hydrogen yield (0.03 LH₂/g VS). The self-fermented anaerobic bioreactor improved sewage sludge utilization, increased bioenergy yields, and seems to be promising for treating complex wastes at this scale. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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21 pages, 3859 KiB

Open AccessArticle

Optimizing Mass Transfer in Multiphase Fermentation: The Role of Drag Models and Physical Conditions

by Yannic Mast, Moritz Wild and Ralf Takors

Processes 2024, 12(1), 45; https://doi.org/10.3390/pr12010045 - 23 Dec 2023

Cited by 1 | Viewed by 2206

Abstract

Detailed knowledge of the flow characteristics, bubble movement, and mass transfer is a prerequisite for the proper design of multiphase bioreactors. Often, mechanistic spatiotemporal models and computational fluid dynamics, which intrinsically require computationally demanding analysis of local interfacial forces, are applied. Typically, such [...] Read more.

Detailed knowledge of the flow characteristics, bubble movement, and mass transfer is a prerequisite for the proper design of multiphase bioreactors. Often, mechanistic spatiotemporal models and computational fluid dynamics, which intrinsically require computationally demanding analysis of local interfacial forces, are applied. Typically, such approaches use volumetric mass-transfer coefficient (k_La) models, which have demonstrated their predictive power in water systems. However, are the related results transferrable to multiphase fermentations with different physicochemical properties? This is crucial for the proper design of biotechnological processes. Accordingly, this study investigated a given set of mass transfer data to characterize the fermentation conditions. To prevent time-consuming simulations, computational efforts were reduced using a force balance stationary 0-dimension model. Therefore, a competing set of drag models covering different mechanistic assumptions could be evaluated. The simplified approach of disregarding fluid movement provided reliable results and outlined the need to identify the liquid diffusion coefficients in fermentation media. To predict the rising bubble velocities u_B, the models considering the Morton number (Mo) showed superiority. The mass transfer coefficient k_L was best described using the well-known Higbie approach. Taken together, the gas hold-up, specific surface area, and integral mass transfer could be accurately predicted. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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14 pages, 2950 KiB

Open AccessArticle

Scalable and High-Throughput In Vitro Vibratory Platform for Vocal Fold Tissue Engineering Applications

by Andreea Biehl, Ramair Colmon, Anastasia Timofeeva, Ana Maria Gracioso Martins, Gregory R. Dion, Kara Peters and Donald O. Freytes

Bioengineering 2023, 10(5), 602; https://doi.org/10.3390/bioengineering10050602 - 17 May 2023

Cited by 3 | Viewed by 2218

Abstract

The vocal folds (VFs) are constantly exposed to mechanical stimulation leading to changes in biomechanical properties, structure, and composition. The development of long-term strategies for VF treatment depends on the characterization of related cells, biomaterials, or engineered tissues in a controlled mechanical environment. [...] Read more.

The vocal folds (VFs) are constantly exposed to mechanical stimulation leading to changes in biomechanical properties, structure, and composition. The development of long-term strategies for VF treatment depends on the characterization of related cells, biomaterials, or engineered tissues in a controlled mechanical environment. Our aim was to design, develop, and characterize a scalable and high-throughput platform that mimics the mechanical microenvironment of the VFs in vitro. The platform consists of a 24-well plate fitted with a flexible membrane atop a waveguide equipped with piezoelectric speakers which allows for cells to be exposed to various phonatory stimuli. The displacements of the flexible membrane were characterized via Laser Doppler Vibrometry (LDV). Human VF fibroblasts and mesenchymal stem cells were seeded, exposed to various vibratory regimes, and the expression of pro-fibrotic and pro-inflammatory genes was analyzed. Compared to current bioreactor designs, the platform developed in this study can incorporate commercial assay formats ranging from 6- to 96-well plates which represents a significant improvement in scalability. This platform is modular and allows for tunable frequency regimes. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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25 pages, 8837 KiB

Open AccessArticle

Study on Scale-Up of Anaerobic Fermentation Mixing with Different Solid Content

by Zhe Li, Hancheng Lu, Zixuan Zhang and Baoqing Liu

Fermentation 2023, 9(4), 375; https://doi.org/10.3390/fermentation9040375 - 14 Apr 2023

Cited by 3 | Viewed by 3818

Abstract

The scale-up technology of anaerobic fermentation stirring equipment is worthy of attention. Computational fluid dynamics (CFD) simulations were used to study the scale-up of anaerobic fermentation mixing under different solid content conditions. The applicability of different scale-up criteria was analyzed by investigating the [...] Read more.

The scale-up technology of anaerobic fermentation stirring equipment is worthy of attention. Computational fluid dynamics (CFD) simulations were used to study the scale-up of anaerobic fermentation mixing under different solid content conditions. The applicability of different scale-up criteria was analyzed by investigating the relative parameters, such as the blade tip speed and the Reynolds number. On this basis, the scale-up index was optimized and verified. The results revealed the applicability of five common scale-up criteria under different solid content conditions. When the solid content is less than 5%, the anaerobic fermentation tank should be scaled up according to the same Weber number. When the solid content is between 5% and 10%, the anaerobic fermentation tank should be scaled up according to the same blade tip speed; it was especially suitable for anaerobic fermentation and other conditions that limit the shear rate. Scaling up according to the Reynolds number was not recommended due to the poor mixing effect. When the scale-up index x reached 0.75, there was no need to further reduce it. For anaerobic fermentation systems, the suitable scale-up indices selected for 5%, 10%, and 15% solid content were 1.1, 1, and 0.75, respectively. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications - 2nd Volume)

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