We recently finished our Ask the Expert discussion on Options for Increasing Output and Reducing Footprint in Adherent Cell Culture. This week we had several interesting questions and informative responses. Specific information was provided on using fixed bed bioreactors to culture various adherent cell lines. There were also questions regarding increasing output, culturing cells as the product, large-scale production and cost benefits.

Adherent cell culture is often used in the manufacture of biologic products, including vaccines. Historically, the surface for cells to adhere to has been provided either by a two-dimensional (2D) system such as roller bottles, T-flasks, cell factories or cell stacks; or microcarrier beads within a traditional stirred tank bioreactor. However the need to increase product production and reduce manufacturing footprints have led to the creation of novel solutions.

One alternative solution to traditional 2D systems and to a microcarrier-stirred tank option is a fixed-bed disposable bioreactor, which can provide efficient scale-up and manufacturing with a small footprint.

This Ask the Expert Session was Sponsored by Pall Life Sciences and hosted by. Jose Castillo, Director of Cell Culture Technologies. Jose Castillo transitioned into his role as Director of Cell Culture Technologies for Pall Life Sciences during the December 2013 acquisition of ATMI LifeSciences. Before this time, Jose was one of the original founders and acting CTO at Artelis, which ATMI LifeSciences acquired in November 2010. Throughout his career, Jose has been heavily entrenched in development aspects for “process intensification” in disposable bioreactors and related processes for vaccine and antibody applications, as well as for the expansion of stem cells.

Prior to founding Artelis, Jose worked as the Manager of Viral Vaccine Industrialization for GSK Biologicals. He has a general background in Chemical Engineering, including a PhD in Applied Sciences from the Université libre de Bruxelles, and an entrepreneurship degree from the Solvay Business School.

Below is a sneak peek of the discussion. For a full transcript of the discussion, please see – Ask the Expert – Options for Increasing Output and Reducing Footprint in Adherent Cell Culture.

Question:

What do you think is the best way to culture HEK293 cells? Could you use this system?

The Answer:

If HEK is in suspension: Grow them in shaken flasks until you reach the desired cell density, then seed the iCELLis bioreactor. From there, grow them until the desired density for transfection and then proceed with addition of the viral vector and transfection reagents.

If HEK is in adherence: Do the same, but replace the shaken flasks of pre-culture by static multitray systems. As before, grow them in shaken flasks until you reach the desired amount of cells, then seed the iCELLis bioreactor. From there, grow them until the desired density for transfection is reached, and then proceed with addition of the viral vector and transfection reagents.

Question:

Can you please walk through where the cost savings are by switching from roller bottles to a fixed-bed bioreactor?

The Answer:

One of the greatest benefits of replacing roller bottles with a fixed-bed bioreactor is that one system takes the place of many hundreds (to thousands) of roller bottles. In the case of the fixed-bed bioreactor, we are able to create the surface space in one system by using microcarriers.

As an example, if you replace a 500-roller bottle system with a fixed-bed bioreactor like the iCELLis^™ bioreactor, cost savings come from:

Reduced Manpower: Only one operator is needed to operate only one system. This is a drastic reduction in manpower from the 500 operations that would be needed to accommodate the roller bottles.

Minimized Space/Accommodation: Only one bioreactor needs to be housed instead of 500 stacked bottles in a roller bottle machine. This creates a 10- to 50- fold savings in the amount of space needed to accommodate the process.

Decreased Waste: Dramatically decreases the number of aseptic operations and the risk of contamination—less scrap from batches.

Question:

Is there an upper limit to the volume of production for a fixed-bed system? Could this be used for large-scale production; if so, do you lose some of the footprint/cost benefits?

The Answer:

We currently work with an upper limit of 25L (replacing up to 6,000 roller bottles), and have found that this more than accommodates most customers’ applications in the human and animal vaccine business. In other words, it is not a limitation.

In reality, there is a geometric limitation on how large it could be. While it would be possible to scale this up to 50L in the future, it would not make sense to go any larger than that from an applications and engineering perspective.