Single-Use Technology for Microbial Fermentation

Sponsored by: GE Healthcare
Session ends: Closed
Answers by: Ken Clapp, Senior global product manager for single-use stirred-tank bioreactors and fermentors.


Microbial fermentation processes are used for biomanufacturing of various drugs and vaccines, such as hormones, antibody fragments, and pneumococcal vaccine. Stirred-tank fermentors up to 100,000 L scale have traditionally been used in such microbial processes and their success has formed the general engineering foundation and principles of the design of bioreactors. The majority of today’s fermentation processes are performed in bioreactors constructed of traditional materials such as stainless steel. However, there is an increased interest in disposable technology to gain flexibility, save batch change-over time, and minimize cleaning and cleaning validation efforts.

To date, single-use stirred-tank bioreactors for mammalian and insect cell cultures have been successfully used in scales up to 2,000 L working volume and are installed in both clinical and commercial drug manufacturing facilities. However, for bioreactors to be utilized in microbial fermentation some engineering challenges needed to be addressed. For instance, fermentors had to be designed to handle very high metabolic rates and the high oxygen demands of some microbial cultures. By applying general bioengineering principles and designs, high oxygen transfer rates can be achieved also in disposable fermentors. Augmented designs and operational methods compensate for the low heat transfer rates in these systems. Although pressurizable single-use stirred-tank fermentors are within the realm of the technical feasibility, this feature might not be necessary as sufficient oxygen transfer can be achieved through a variety of mechanical and process control designs and techniques.

For more information on the use of single-use in microbial fermentation, please see:
Cell Culture Dish – “Single-use Technology for Microbial Fermentation”

This session is sponsored by GE Healthcare

Questions & Answers

How would you recommend testing scale up conditions prior to moving to the single use bioreactor? Are there any differences to be aware of between using single use and stainless steel?

Simulated process modeling, using current known process data typically provides the necessary feasibility information. About the technologies, for processes that are transferable, single-use offers an equivalent platform to stainless. There may be unique processes not suited for single-use. Media and additives cannot be sterilized in the bag, but rather externally. Consider your motivation for implementing […]» Read More

In single use microbial applications how would you recommend addressing the challenges of low oxygen transfer and cooling issues that have been discussed?

In steam sterilizable, or conventional fermentors, we have had the ability to deliver more horsepower to the agitation system and oxygen to the sparging system than was sometimes needed; an overabundance of capacity, at times. With single-use fermentors, efficiency, especially in the process is the premium. Single-use fermentors are capable of controlling dissolved oxygen with […]» Read More

We are looking to manufacture a few different products mammalian and microbial in the same location. We have looked at a few of the flexible facility models for mammalian cell culture. Do you believe that a similar approach using single-use in microbial fermentation and single-use for mammalian would be effective? If so, are there any aspects of planning that you would recommend considering?

Very definitely…the flexibility imparted to fermentation, like in cell culture, is analogous. If I interpret your question further, might I also say that dual-purpose systems, systems capable of either cell culture or fermentation by switching reactor bags and some accessories are available. This type of dual-purpose product provides another level of flexibility, especially for development […]» Read More

Are there any vaccine targets that you would not want to manufacture using single-use systems maybe a highly infectious/toxic target or some other factor? Are there any special conditions that should be considered?

Application of single-use technology does not relieve the process owner from assessing any and all appropriate risks. The infectiousness or toxicity of a process, process intermediate or end-product should be considered, with operator safety being paramount. Unlike stainless steel fermentors, single-use fermentors rely on plastic films, tubing, etc. There are risks, though low, of breaches […]» Read More

It seems that single-use is a good option for new processes, but for existing processes what points would you consider when deciding whether to change to single-use?

Single-use technology is a good option for new and existing processes. There may be more to evaluate for existing processes because is it already operational. Consider that single-use technology shortens the turnaround time thereby, effectively, increasing equipment utilization. The industry remains very competitive and saving time had direct benefit to the bottom line. Also consider […]» Read More

Is there technology to support a fully single-use system for microbial fermentation? I mean are there any parts that still need to be cleaned validated?

With respect to the process contacting parts, which is the bioreactor/fermentor bag, there is nothing to clean as nothing gets reused from that assembly. This is one of the main benefits of single-use bioprocess technology as a whole. And, specifically, for fermentation, single-use technology eliminates cross-contamination previously associated with O-rings, gaskets, diaphragms and mechanical seals. […]» Read More

Can you tell me whether there would be cost benefit from switching to single-use technology in microbial fermentation and if so, from where?

Equipment utilization will be much greater due to the faster turnover between runs. Single-use avoids post-run CIP, cleanliness validation, sterilization and pressure testing. The risk of cross-contamination is virtually eliminated. The consumption of water in CIP and sterilization is tremendous. Maintenance is almost non-existent by comparison; with no seals, O-rings or gaskets to replace between […]» Read More