November 15, 2014 (Vol. 34, No. 20)

Gail Dutton

Danish Company Focuses on Configurable-Batch, Single-Use Bioreactors and Fermenters

Denmark-based CerCell specializes in single-use bioprocess products. According to company founder and CEO Per Strobbe, the company’s expertise lies in its ability to offer fully customizable, scalable single-use bioreactors and single-use fermenters.

When asked about why he thinks his company is so well positioned in the single-use market, Stobbe opens a suitcase, revealing a hoard of impellors, turbines, spargers, hose assemblies, baffles, drives that connect to servo motors, temperature control devices, fluid in-and-out methods, exhaust methods, mixers, and sensors.

Stobbe encourages his listeners to think of the components as LEGO-like building blocks: “I say, ‘Let’s be creative and assemble the bioreactor or fermenter you want.’”

A Startup with a Long History

CerCell is no startup; it has 30 years of history stemming from its parent, Stobbe Tech, a privately owned research company.

Focused tightly on R&D, Stobbe Tech transfers manufacturing and marketing duties to its specialized daughter companies, including CerCell. In 2007, Stobbe Tech participated in a research project that was funded by the European Union. The project resulted in the customizable, scalable, single-use bioreactors and single-use fermenters CerCell markets now.

Stobbe himself, with degrees in materials engineering and fluid dynamics, wrote 55 patents. “We don’t want to copy others,” he emphasizes. “We design, develop, and manufacture only products of our own design.” His company’s early products remediated air and water pollution before evolving to address biotech issues. CerCell’s customizable bioreactors have been available for less than one year, and its customizable fermenter was launched during the summer.

The BactoVessel fermenter holds up to 60 L for microbial fermentation. The scalable single-use bioreactor, CellVessel, has a working volume of up to 75 L. A relatively standard, 3 L, single-use bioreactor also is available for suspension cell lines used for protein expression.

“Standard,” however, seldom quickens the user’s creative pulse. “Customized single-use bioreactors or single-use fermenters are by far the most interesting to design together with the user,” Per Stobbe emphasizes.

The bioreactors support both batch and fed-batch reactions, including various first-stage downstream filters. The bioreactors and the fermenter are compatible with existing and classical sensors; single-use sensors from Broadley-James or Hamilton; and CerCell’s own open platform process control system, currently in development.

In terms of developing products, CerCell’s approach is simple: “Listen to end users’ requirements and develop what they want,” Stobbe relates. “By listening, we saw the need for a customizable product.” At CerCell, “custom” is the watchword. “If you can explain it,” Stobbe insists, “we can design the single-use bioreactor or single-use fermenter you prefer.”

The CellVessel series of single-use bioreactors from CerCell is suitable for batch and fed-batch cultivation of various cell lines in suspension. Different CellVessel configurations can be created by selecting from hundreds of different components.

High-Performance Disposables

Stobbe explains that CerCell’s single-use bioreactors and single-use fermenters are made from rigid plastic which allows them to operate without the leachables and extractables issues that can plague some soft, flexible plastic systems. As Stobbe points out, “Making plastic flexible requires adding chemicals—typically phthalate plasticizers. Because we don’t use soft plastics, we don’t have the associated problems of extractables and leachables.”

Rigid single-use fermenters also allow the creation of high-performance microbial applications, he claims. In some available flexible film bags, Stobbe elaborates, turbines spin at no more than 500 revolutions per minute (RPMs). In a rigid fermenter, however, turbines may spin at 1,500 or 2,000 RPMs in between any preferred baffles design. “The use of rigid plastic results in a new, high-RPM product for the industry, designed the way you want, and scaleable from 1 to 60 L,” Stobbe says.

The ability to choose impellors or turbines imparts better control of product gradients within the bioreactor or fermenter. Historically, Stobbe explains, “gradations within the bioreactors have been a real problem that reduces output.”

According to Stobbe, CerCell’s LEGO-like approach allows scientists to determine their exact requirements for flow dynamics inside the bioreactors and fermenters, and to combine the right the impellor, turbine, stator, and baffles, arriving at the system best suited to satisfy those requirements. Stobbe asserts that CerCell’s tests show more even growth patterns inside the bioreactor and faster bacterial growth in the fermenter.

Mix-and-match components for CerCell’s CellVessel include impellers, rotating elements that deliver or absorb energy. The company’s IMPellers are designed with individual blades attached to the central core.

The Future of Single Use

Disposable manufacturing is a precursor to the development of continuous manufacturing. The company currently has working prototypes that function continuously for two months. “Traditional bioreactors commonly yield 5 million cells per mL. Our designs can harbor between 150 million and 200 million cells per mL,” Stobbe says. With such density, the need for large traditional batch bioreactors (and the floor space they require) will decrease.

CerCell is designing scalable perfusion single-use bioreactors and the necessary advanced, scalable process control system to support the continuous mass production of antibodies. The company plans to realize its work on this technology in about one year.

Such disruptive technologies will take time to be embraced, Stobbe notes. In the meantime, however, CerCell is launching fully customizable bioreactors and fermenters—products that already have a defined market.


Location: Malmmosevej 19C, DK-2840 Holte, Denmark

Phone: +45 4542 3393


Principal: Per Stobbe, Founder and CEO

Number of Employees: 15

Focus: CerCell develops and manufactures fully customizable, single-use bioreactors and fermenters for microbial  reactions, using advanced applications of materials science and fluid dynamics.

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