Advantages of single-use bioreactors and fermenters over traditional bioprocessing

Single use bioreactors and single use fermenters (SUBs and SUFs) have recently grown in popularity as they meet the constant demands of the biopharmaceutical industry for lower costs, increased efficiency, and overall greater flexibility. While conventional bioreactors still work for some processes, SUBs and SUFs are often the better choice for rapidly-growing markets in drug development, testing, and manufacturing.

What is single-use bioprocessing equipment?

Traditional bioreactors and fermenters are made of stainless steel or glass. In contrast, the vessels for SUBs and SUFs are disposable plastic bags that are installed into outer metal containers.

The vessel usually arrives pre-sterilized, with all impellers, spargers, and sensors already installed or built in. Most often, these bags are made of a three-layer plastic foil. The outermost layer is made of LPDE, providing mechanical stability; the middle layer is made of PVA or PVC, creating a gas barrier; and the innermost layer is composed of sterilized PVA or PP.

Single-use for benchtop-scale processes

In benchtop-scale processes, SUBs and SUFs can often be used interchangeably. There are two types of benchtop SUB/SUF systems on the market, differing primarily in their approach to mixing/agitating the cell media.

The first type uses a stirrer, much like a conventional bioreactor, to constantly mix the cell culture. These stirrers are usually built into the plastic vessel and are pre-sterilized, acting as a turnkey solution.

The second type of system uses a rocking apparatus to mix the media, which is preferable for certain media types. Manufacturing these vessels is also simpler as it does not require any pre-installed mechanical parts.

Comparing bioreactors and fermenters for large-scale processes

While often interchangeable at small scales, bioreactors and fermenters are highly specialized to specific culture types at large scales. Both of these technologies require regulation of pH, temperature, pressure, and oxygen levels to maintain cell growth, although they differ in their applications and production methods.

Bioreactors are used to produce biologics and biosimilars – peptides, antibodies, vaccines, and pharmaceuticals – using plant or animal cells. Pharmaceutical applications most often grow Chinese Hamster Ovary (CHO) cells through biochemical reactions. Meanwhile, fermenters are used to produce acids and alcohols through fermentation of microbes.

Advantages of single-use over traditional stainless steel

1.     Sterilization

SUBs and SUFs come pre-sterilized and are disposed of after use. Single-use systems thereby minimize any chance of cross contamination – which can completely ruin a batch. This also eliminates the weeks of downtime required for sterilizing reusable stainless steel vessels.

2.     Flexibility

Conventional bioreactors and fermenters have a single design, which limits the features that can be manipulated in the experiment. In contrast, there are various types of single-use vessels available, allowing the scientist or process developer to pick and choose the best vessel design for their process. Single-use also makes it easier to experiment with various designs to optimize the process. Ultimately, this flexibility allows for much simpler experimentation and scale-up meaning increased yields and lowered costs.

3.     Energy savings

Single-use systems offer reduced energy consumption, water consumption, and environmental footprint of the plant overall. Traditional systems require a considerable amount of on-site infrastructure, which in turn requires more energy and water for operation and cleaning. One estimate shows that biopharmaceutical production facilities using SUBs or SUFs could reduce their overall energy & water consumption by 46% and carbon footprint by 35% when compared to conventional facilities.

Are there disadvantages to single-use?

The main constraint of single-use equipment is its inability to scale into the manufacturing stage. Single-use vessels of up to 2,000 liters are fairly new, while conventional bioreactors and fermenters are often used to produce 10,000 liter batches.

However, single-use technology is enabling rapid growth and innovation. The significant advantages of single use bioreactors and fermenters over traditional bioreactors and fermenters explain why single-use technology has been adopted so readily.