On the Path to Circularity: Sartorius and Covestro Prove the Recycling Potential of Small-Scale Bioreactors

Magali, let’s start at the beginning. Not all plastics used in the biotech industry are the same, can you give us an overview?

Indeed, the generic term “plastics” covers many materials designed to meet very different needs. Plastics are made from a wide range of polymers which are mixed with chemical compounds that protect them and improve material performance, for example regarding resistance to oxidation and UV light, fire-retardancy, and physical properties. The different types of plastics add complexity to recycling concepts.

Which special requirements must plastics fulfill in our industry? What are the challenges?

In the biopharma industry, single-use product designers face a complex set of demands when selecting materials, particularly to ensure both process efficiency and patient safety. These technologies must meet stringent requirements throughout their lifecycle, such as withstanding sterilization, maintaining structural integrity during transportation and storage, reliably serving their function in bioprocessing, and ultimately being manageable as process waste.

In addition, materials that get in contact with our customers’ products must be designed with minimized extractables for patient safety. And finally, the demand for extended shelf life imposes additional challenges. Our material engineers’ task is to integrate all these requirements across diverse process applications – which requires meticulous material selection and engineering.

When talking about recycling, what are the main challenges of plastics recycling in the biopharmaceutical industry?

There is a two-fold challenge, covering end and beginning of life of a plastic product: First, to recycle plastic products which are very often considered as “contaminated” and second to incorporate recycled plastic in new plastic products, because recycling is perceived as unsuitable for high-quality-applications – in some cases even forbidden.

Additionally, recycling is expected to have a better environmental impact. And on top of that, recycling should not cost more.

All in all, this is why retaining the value of our plastics, which are of excellent quality, is one of our goals.

Together with Covestro, you developed a concept to find solutions for recycling plastics of small-scale bioreactors. How did the collaboration come about?

Sartorius’ Corporate Research department works in close collaboration with many external partners on innovation projects. Our goal is to identify and develop key technologies and application fields of the future.

Covestro’s approach for Polycarbonate circularity is in line our own thinking, and so it was an easy decision to work together on a concept, and bring our respective expertise on board.

Tell us more about the project. What did you work with and what are the key findings?

Our first goal was to challenge the perception of mechanically recycled plastic as poor quality. And we have succeeded in proving that the polycarbonate vessels of our Ambr small-scale bioreactors can be recycled in a closed-loop for a cell culture application – provided they are collected, disconnected, sorted, and recycled. These last four steps, however, are still open challenges, which strongly depend on local recycling infrastructure.

We have succeeded in proving that the polycarbonate vessels of our Ambr small-scale bioreactors can be recycled in a closed-loop for a cell culture application – provided they are collected, disconnected, sorted, and recycled.

Magali Barbaroux, Corporate Research Fellow

Our second goal was to assess the environmental impact of recycling compared to the current end-of-life scenario of a small-scale plastic bioreactor. What we found was that recycling has a positive impact on de-fossilization and resource depletion. Our approach to recycling performs better in terms of climate impact compared to the conventional ‘use and dispose’ process. The extent of this depends on how much material is recycled, how often it's returned and whether the recycling process is closed-loop or open-loop - meaning is the material used to make the same type of product or something different. However, even in less ideal scenarios, the impact is always positive and a step in the right direction.

Single-use technologies based on plastics are widespread within the life science industry. Can the results be transferred to other products?

The small-scale bioreactor closed-loop recycling is already the second single-use technology recycling concept, the first one being the recycling Flexsafe^® film concept for buffer and media bags in an open-loop (in another application) with Veolia and Sanofi. Recycling highly depends on materials, but also on the application and regional infrastructure. A “one-size-fits-all” solution seems unrealistic today. Instead, we need a toolbox of recycling solutions. Each concept contributes to our learning curve and expands our collaborative network, which is mandatory for successful recycling.

The proof of concept project has shown that the quality of the recycled plastic can be on the same level as virgin plastic. What does this mean for the future use of secondary plastics in our products?

Right, the concept provided proof for technical recyclability. Technical recycling, however, is a necessary but not a sufficient condition for our products to be recycled. In other words: We have taken the first, very important step on the recycling path. And we have more steps ahead of us.

We have taken the first, very important step on the recycling path. And we have more steps ahead of us.

Magali Barbaroux, Corporate Research Fellow

To realize recycling on a large scale, what conditions must the product meet and what requirements must each customer provide on-site?

Sartorius has the responsibility to design its products with recyclability in mind. Of course, “design to recycle” cannot compromise quality and function, but it must be assessed and implemented whenever possible.

To date, valuable recycling requires efficient collection, sorting and disconnection prior to the recycling process. Where and how this can be done are still open questions which we aim to answer through pilot projects with our customers.