Related Experiment Video
Updated: Jun 27, 2026
08:13
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Bioreactor scale-up and oxygen transfer rate in microbial processes: an overview
Felix Garcia-Ochoa1, Emilio Gomez
1Dept. Ingeniería Química. Facultad Químicas, Universidad Complutense, 28040-Madrid, Spain. fgochoa@quim.ucm.es
Biotechnology Advances
|December 2, 2008
Summary
Accurate prediction of oxygen transfer rate (OTR) is vital for optimizing aerobic bioprocesses. This review covers OTR measurement, prediction methods, and bioreactor scale-up criteria, considering cell oxygen uptake.
Area of Science:
- Biochemical Engineering
- Bioprocess Technology
- Mass Transfer
Background:
- Oxygen is crucial for aerobic bioprocesses but has low solubility, necessitating efficient oxygen transfer.
- Oxygen transfer rate (OTR) and oxygen uptake rate (OUR) by microorganisms significantly impact dissolved oxygen levels.
- Bioreactor design and scale-up depend on understanding hydrodynamic conditions influencing gas-liquid mass transfer.
Purpose of the Study:
- To review oxygen transfer rate (OTR) in bioprocesses for improved bioreactor selection, design, operation, and scale-up.
- To provide comprehensive knowledge on OTR measurement and prediction methods.
- To analyze bioreactor scale-up criteria considering OTR and OUR.
Main Methods:
- Review of established and novel methods for measuring the volumetric mass transfer coefficient (k(L)a).
- Analysis of empirical equations, including those utilizing dimensionless numbers, for OTR prediction.
- Inclusion of the biological enhancement factor to account for cell oxygen consumption.
Main Results:
- Discussion of theoretical predictions for volumetric mass transfer coefficient (k(L)a) and enhancement factor.
- Evaluation of various bioreactor types (stirred tanks, bubble columns, airlifts) based on mass transfer and hydrodynamic properties.
- Consideration of operational conditions, physicochemical properties, and bioreactor geometry effects on OTR.
Conclusions:
- Accurate OTR and k(L)a measurement/prediction are critical for efficient bioreactor design and scale-up.
- Understanding the interplay between OTR, OUR, and hydrodynamic conditions is essential for process optimization.
- This review offers insights into selecting and developing optimal bioreactor systems for aerobic bioprocesses.
Related Concept Videos
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
01:14Scale-Up Processes
The scale-up of microbial fermentation processes is essential in industrial biotechnology, allowing the transition from laboratory-scale experiments to commercial-scale production while aiming to maintain product yield and quality. This process requires meticulous adjustment of equipment design, process parameters, and contamination control strategies to accommodate increasing culture volumes.At the laboratory scale, cultures are typically maintained in 1 to 10-liter glass or autoclavable...
01:29Bioreactor Design and Operational System
Bioreactors are engineered vessels designed to cultivate microorganisms under controlled conditions for industrial bioprocessing. They maintain sterility and allow precise regulation of pH, temperature, oxygen, and nutrient levels to optimize microbial growth and metabolite production. Bioreactors range from small laboratory units of 1 liter to industrial systems holding up to 500,000 liters, though only about 75% of their volume is actively used for fermentation. The remaining headspace...
01:28Bioreactor Controls-I
Maintaining optimal conditions within fermenters is essential for maximizing microbial productivity and ensuring process efficiency. This lesson focuses on key parameters—temperature, foam, pH, carbon dioxide, oxygen, and pressure—and their precise measurement and control strategies in fermentation systems.Temperature ControlTemperature regulation is critical due to the exothermic nature of many fermentation processes. In small laboratory fermenters, temperature is commonly monitored using...
01:27Upstream Processing
Upstream processing represents a critical phase in biomanufacturing, wherein biological systems such as microorganisms, mammalian cells, or insect cells are cultivated to produce therapeutic proteins, vaccines, enzymes, or other biologically derived products. This phase encompasses all steps from the selection and genetic manipulation of the production organism to the cultivation of cells in bioreactors under tightly controlled environmental conditions.Host Selection and Genetic OptimizationThe...
01:30Designing Growth Media for Bioreactors
Growth media provide essential nutrients that support cell growth and metabolism, thereby enhancing the yield of valuable products such as enzymes, antibiotics, and biomass. Designing an effective growth medium involves balancing all components to prevent nutrient limitations or toxic excesses, both of which can impair growth and reduce product yields.Composition of a Typical Growth MediumA typical growth medium contains carbon and nitrogen sources, salts, vitamins, trace elements, and...