Bioreactors and Cell Culture Media: A Practical Comparison for Upstream Bioprocessing

Bioreactors and cell culture media are core components of upstream bioprocessing, supporting applications such as monoclonal antibody and vaccine production.  Together, they define the physical and biochemical environment required for cell growth, protein expression, and product consistency. As a result, the selection of both plays a critical role in determining manufacturing performance, scalability, and long-term process robustness. 

Bioreactor configuration and media formulation can affect critical factors such as cell density, product yield, product quality attributes, and overall cost of goods. They also impact how efficiently a process can scale from early development through clinical manufacturing and to commercial production.

The bioprocessing sector has seen rapid adoption of single-use technologies, with the global single-use bioprocessing market size anticipated to reach USD 33.67 billion by 2030. There is a shift towards sophisticated automation systems and chemically defined media formulations that improve reproducibility and regulatory compatibility. Major suppliers now offer portfolios across different scales and workflows. This diversity can make technology selection more complicated and understanding how these differ is important when evaluating potential upstream processing strategies. As a result, comparing solutions across suppliers has become increasingly complex, particularly as companies balance performance, scalability, regulatory requirements, and supply chain reliability.

Here, we aim to provide a high-level comparison of bioreactor systems and cell culture media by leading bioprocessing suppliers, outlining how different technology platforms are positioned and where they are commonly used across the bioprocessing landscape.

Key evaluation criteria of bioreactors

1. Scale and scalability

Bioprocesses often begin at small laboratory scales and must later be transferred to pilot and commercial manufacturing. Bioreactor scale-up influences chemical, physical, and biological factors.  A biologic manufacturing process typically involves scaling up of production from small throughput bioreactors (15–250 mL) to bench-scale glass or single-use reactors (1–10 L), and then pilot- and production-scale bioreactors (200–5,000 L or larger).  Some suppliers emphasise  modular single-use systems that can scale within disposable formats, while others provide both single-use and stainless-steel solutions to support different manufacturing strategies.

2. Single-use vs stainless steel

Single-use bioreactor bags reduce the need for cleaning and sterilisation, which can shorten turnaround times (TAT) and reduce the complexity of facility operation.  However, stainless-steel bioreactors remain widely used in large commercial facilities, particularly where long-term manufacturing campaigns benefit from lower consumable costs and established infrastructure. As a result, many organizations maintain a combination of both system types across development and production environments.

3. Process control and automation

Modern bioreactors may incorporate automated control of parameters such as pH, dissolved oxygen, temperature, agitation, and nutrient feeding. Integration with digital systems, including manufacturing execution systems and data analytics platforms, is also becoming more common. The level of automation and software functionality can therefore influence how easily a platform fits into broader manufacturing operations.

4. Mixing and oxygen transfer

Bioreactor design affects mixing efficiency, gas transfer rates, and shear stress experienced by cells. These characteristics influence cell viability and productivity, particularly in high-density mammalian cultures where oxygen demand and metabolite accumulation can become limiting factors. Different bioreactor configurations, such as stirred tank, wave, or rocking systems, offer different performance characteristics depending on the specific process.

5. GMP readiness

For clinical and commercial manufacturing, equipment must support Good Manufacturing Practice (GMP) compliance. This includes documentation, validation capabilities, and traceability of components used within the system. Suppliers that provide established GMP-compatible platforms may therefore be preferred when processes are expected to transition into regulated manufacturing environments.

Key evaluation criteria in cell culture media

1. Chemically defined vs complex formulations

Historically, many media formulations included undefined components such as serum or hydrolysates. However, modern biologics manufacturing increasingly favours chemically defined media, in which all components are precisely specified. Chemically defined formulations can improve process consistency and simplify regulatory filings by reducing variability associated with biological raw materials.

2. Productivity and growth performance

Media composition directly impacts growth, metabolic activity, and protein production levels. Media formulations are often optimised to support high cell densities and high product titres. However, optimal performance can vary depending on the specific cell line and process conditions used.

3. Robustness and process compatibility

Media must function reliably across different stages of development, including small-scale screening and commercial manufacturing. Robust media formulations support will reduce variability risks even when parameters change during scale-up.

4. Supply chain reliability

Secure and consistent supply of media components is critical, as relatively small disruptions can cause significant productivity losses. Manufacturers typically prioritise suppliers with well-established production capacity, raw material traceability, and quality management systems that support long-term manufacturing programs.

Comparison of bioreactor suppliers:

Several major suppliers provide bioreactor systems across the biopharmaceutical industry, with portfolios varying in scale, technology focus, and intended applications. While many suppliers now offer broader bioprocessing ecosystems that include media, automation tools, and downstream technologies, individual bioreactor platforms are often designed to address specific challenges across process development, scale-up, and commercial manufacturing.

Cytiva

Cytiva focuses on single-use bioreactor technologies used in biologics manufacturing, including systems such as the X-platform bioreactors, designed for monoclonal antibody and recombinant protein production. The technology includes next-generation stirred tank reactors, large scale perfusion, and single-use fermentation. The company’s bioreactor portfolio spans clinical and commercial manufacturing settings where disposable systems are preferred for operational flexibility. However, reliance on single-use components can introduce cost and supply considerations. 

Sartorius

Sartorius offers a broad range of upstream bioprocessing technologies spanning from 10 mL up to 2000 L working volumes. Platforms such as Biostat and Ambr are widely used in process development laboratories and manufacturing facilities. With emphasis on modular design and integrated automation, software platforms that manage process monitoring and control are often incorporated into upstream workflows, enabling data-driven optimisation during development and scale-up. However, this system complexity may require specialised expertise.

Thermo Fisher Scientific

Thermo Fisher Scientific provides bioreactors as part of a broader portfolio of bioprocessing technologies, including cell culture media, analytical tools, and manufacturing consumables. Their portfolio of bioreactors and accessories aim to complete the whole system. Its upstream solutions are often used alongside downstream purification technologies within integrated biologics production workflows.  This approach can simplify implementation, although some users may prefer multi-vendor flexibility.

Merck (MilliporeSigma)

Merck offers single-use bioreactor platforms such as Mobius systems for biologics manufacturing. These systems are commonly deployed in facilities producing monoclonal antibodies and other recombinant therapeutics. Merck’s upstream technologies are often integrated with its filtration and purification solutions used in downstream processing. This allows manufacturers to combine upstream and downstream components within a consistent technology framework. As with other single-use systems, considerations such as consumable costs and supply chain management can influence long-term adoption strategies.

Lonza

Lonza operates both as a bioprocess technology provider and a contract development and manufacturing organisation (CDMO). They offer upstream platforms alongside proprietary cell line technologies used in biologics development. These integrated platforms are commonly used by companies seeking end-to-end support for therapeutic protein production. This integrated model can be attractive for companies seeking end-to-end support in biologics development but may limit flexibility for multi-vendor strategies.

Eppendorf

Eppendorf focuses on benchtop and small-scale bioreactor systems used in academic research laboratories and early-stage process development environments. These systems, such as the BioFlo are commonly used for cell culture experimentation, process optimisation, and training applications. Their relatively small scale and flexibility make them suitable for exploratory work where multiple process conditions may be evaluated in parallel but are less suited for large-scale commercial manufacturing environments.

Table 1 compares a selection of widely used bioreactor platforms from leading suppliers, highlighting differences in scale, process capabilities, and typical applications. These platforms illustrate the industry's shift towards single-use technologies, increased automation, and scalable process development strategies.

Table 1.

Comparison of cell culture media suppliers

Cell culture media play a central role in determining cell growth, productivity, product quality, and overall process robustness. Modern biologics manufacturing increasingly relies on chemically defined media formulations that reduce variability and support regulatory compliance. However, media selection remains highly dependent on the specific cell line, production process, and manufacturing objectives.

Cytiva

Cytiva offers broad cell culture media used in both research and industrial bioprocessing, including basal media, feeds, and supplements designed to support mammalian cell growth and recombinant protein expression. Cytiva media platforms are widely adaptable for larger-scale manufacturing workflows and are commonly used during early process development.

Thermo Fisher Scientific

Thermo Fisher Scientific is one of the largest global suppliers of cell culture media for research and commercial manufacturing, offering chemically defined media platforms designed to support high-performance cell culture processes. These are commonly used in CHO (Chinese hamster ovary) cell production workflows and are often paired with optimised feeding strategies to achieve high cell densities. They offer an extensive portfolio and global manufacturing capability to support large-scale supply chains.

Merck (MilliporeSigma)

Merck offers chemically defined media platforms designed for high-performance mammalian cell culture processes. These formulations are widely used in CHO-based biologics production and are often paired with optimized feeding strategies to support high cell densities and productivity. Merck offers high-performance media optimised for productivity, with common applications in monoclonal antibody production and recombinant protein manufacturing. 

Lonza

Lonza offers proprietary cell culture media optimised for use with its cell line development technologies. These media systems are commonly used with the company’s GS expression platform, which supports recombinant protein production in mammalian cells.

Table 2 provides a comparison of representative cell culture media platforms commonly used in mammalian cell culture and biologics manufacturing. While performance varies depending on process conditions and feeding strategies, these examples illustrate how suppliers position their media platforms to support different development and manufacturing needs.

Table 2.

Bioreactor Media Pairing Considerations

Bioreactor systems and cell culture media are closely interconnected and should not be evaluated in isolation. Bioreactor design influences key parameters such as mixing efficiency, oxygen transfer rates, and shear stress, all of which can affect cell growth, productivity, and how cells respond to specific media formulations. For example, high productivity media may require specific agitation or aeration strategies to maintain sufficient oxygen transfer while minimising shear stress that could damage sensitive cells.

Additionally, feeding strategies impact the relationship between media and hardware. Many manufacturing processes use fed-batch cultivation, where nutrients are added throughout the production cycle to maintain cell viability and productivity. Media systems are often developed in conjunction with specific feeding regimens and bioreactor control strategies.

Supplier strategy is also an important consideration, with choices between an integrated vendor ecosystem or a multi-vendor approach. Some suppliers offer coordinated platforms that combine bioreactors, media, and downstream technologies, which can simplify process development and technology transfer. However, many manufacturers use multi-vendor setups to maintain flexibility, reduce supplier dependence, and optimise individual process components.

Final thoughts 

The selection of bioreactors and cell culture media remains one of the most important decisions in upstream bioprocess development, influencing process performance, scalability, product quality, and overall manufacturing efficiency. As the bioprocessing landscape continues to evolve, suppliers are offering increasingly sophisticated platforms that combine single-use technologies, automation, chemically defined media, and integrated development workflows. With suppliers emphasising different capabilities, the most appropriate combination of technologies depends on the specific requirements of the process, including the cell line used, the intended manufacturing scale, and the organisation’s broader development strategy, alongside regulatory considerations and long-term operational objectives. Careful consideration of both bioreactor design and media formulation, and how they interact, remains essential for building reliable and scalable biologics manufacturing workflows. A structured evaluation of these factors can help organisations build robust, scalable, and future-ready manufacturing processes that support both development and commercial success.