12 Types Of Bioreactors

Bioreactors are the core equipment in bioengineering for providing suitable environmental conditions (e.g., temperature, pH, dissolved oxygen, mixing, etc.) to support the biological reaction process of microorganisms, cells or enzymes. According to different design principles, application scenarios and operation methods, bioreactors can be categorized into various types. The following are the common classifications and characteristics:
 

Stirred Tank Reactor (STR)

• Characteristics: Mixing and mass transfer are realized by mechanical stirring (stirring paddle), and dissolved oxygen, temperature and pH can be precisely controlled.
• Applications: Widely used in microbial fermentation (e.g. antibiotics, enzymes), animal cell culture (requires low shear stirring paddle design).
• Variants

Bubble stirred reactors: Combination of gas bubbling and mechanical stirring.
Wave Stirred Reactor: generates waves by shaking the vessel, suitable for shear-sensitive cell cultures.
Airlift Reactor (ALR)

• Characteristics: Liquid circulation driven by gas injection (no mechanical stirring), low shear force, lower energy consumption.
• Application: Suitable for shear-sensitive cells (e.g. plant cells, some mammalian cells) or long-term continuous culture.

Bubble Column Reactor

• Characteristics: Only through the gas bubble to achieve mixing, simple structure, but the mixing efficiency is lower.
• Application: suitable for gas involved in the reaction (such as microalgae culture, wastewater treatment).

Packed Bed Reactor

• Characteristics: Cells or enzymes are immobilized in porous carriers (e.g. gels, fibers) to form a fixed bed layer, and the reaction liquid flows through the bed.
• Application: continuous production of metabolites (e.g. ethanol, organic acids) or enzyme-catalyzed reactions.

Fluidized Bed Reactor

• Characteristics: carrier particles suspended in the liquid or air flow, high mass transfer efficiency, but the operation is complex.
• Applications: wastewater treatment, immobilized enzyme reaction.

Membrane Bioreactor (MBR)

• Characteristics: Combination of biological reaction and membrane separation technology, biomass (e.g. microorganisms, cells) is retained by membrane.
• Applications: wastewater treatment, high-density cell culture, continuous separation of products.

Photobioreactor

• Characteristics: Provide light conditions for the cultivation of photosynthetic microorganisms (e.g. microalgae, cyanobacteria).
• Design: Transparent material (glass or plastic), built-in light source or utilizing natural light.
• Applications: biofuels (algal oils), high value-added products (astaxanthin, beta-carotene).

Single-Use Bioreactor

• Characteristics: Use of disposable bags instead of stainless steel tanks to avoid cross-contamination and shorten cleaning and validation time.
• Applications: vaccine production, drug development in clinical trial stage.

Perfusion Bioreactor

• Features: Continuous addition of fresh media and removal of waste liquid to maintain high cell activity and product concentration.
• Application: mammalian cell culture (e.g. monoclonal antibody production).

Batch Reactor

One-time addition of culture medium, product harvesting after the end of the reaction, simple operation but lower efficiency.

Continuous Reactor

Continuous input of culture medium and output of products, suitable for large-scale industrialized production.

Fed-Batch Reactor

Gradually replenish nutrients in batch operation to prolong the cell growth period and increase product yield (commonly used mode).

• Microbial fermenter: such as the production of antibiotics, amino acids.
• Animal cell reactor: e.g. CHO cell production of antibodies.
• Plant cell reactor: such as the production of secondary metabolites (paclitaxel).
• Enzyme reactors: immobilized enzymes catalyze reactions (e.g. glucose isomerization).

• Characteristics of the biological system: microorganisms, animal/plant cells need for shear, dissolved oxygen.
• Product type: whether continuous separation is required (e.g. membrane reactor).
• Scale: laboratory grade (<10 L) vs. industrial grade (>1000 L).
• Cost: disposable reactors for flexible production, stainless steel reactors for long term large scale use.