Why do Ultra Yield™ Flasks work better than glass flasks, and other disposable baffled flasks for E. coli, Pichia, Pombe, Scizomyces?
Ultra Yield™ Flasks (patented) are a disposable high aeration shake flask or bioreactor. Ultra Yield™ Flasks achieve high aeration with a 6 baffle design that has been optimized for fermentation for E. coli, Pichia, Pombe, Scizomyces, and other microbes. They provide good airlift with high speed shaking giving an increase of 10-fold oxygenation, and when combined with nutrient enriched media and proper pH balance, can increase yield significantly. No cutting of aluminum foil, and exposure to cross contamination with used flask plugs. Ultra Yield™ Flasks allow for scalable results from the 125mL, 250mL and 500mL up to the 2.5L.
How does the yield increase with Ultra Yield™ flasks?
The Ultra Yield™ Flasks work to grow more biomass or cells acting as a disposable bioreactor. This leads to increased protein or DNA, and with an increase in density there comes an increase in yield. Cells in Ultra Yield™ Flasks can be grown for over 24 hours, because it is not oxygen limited. Cells do not go from log phase to stationary phase but, as shown by data from GSK, go to a transition phase. This transition stage allows for continued growth without anaerobic conditions that use the cells’ own nutrients to continue its living without stressing the system. pH maintenance is extremely important, buffering with a non-temperature dependent buffer like MOPS makes a large difference in cell growth with the Ultra Yield™ Flasks. Ultra Yield™ Flasks allow for optimum growth in shake flasks, and allow for scalable results from the 125mL to 2.5L flask. In studies and testing we have found that Ultra Yield™ Flasks result in consistent standardized results.
What ratio of liquid media can we have in the Ultra Yield™ Flasks for E. coli and microbes? What are the recommended speeds for E. coli and microbes?
Media ratio depends on the cells being grown. A general rule for E. coli is to use a 40% fill volume. In the 2.5L, some people put 500mL for maximum OD, and others use 1L. They use 3 to 4 flasks to replace a small-scale fermenter.

Recommended speeds:

Recommended culture volumes and orbital shaker speeds (a throw of 1″ is generally used for orbital shaking)
Part # Description Use AirOtop™ Seal Media (mL)/Flask Shaker Speed
931147 125mL Ultra Yield™ Flasks 50/case — Sterile 899421 40-50mL/flask 300-350 RPM
931144 250mL Ultra Yield™ Flasks 50/case — Sterile 899423 75-110mL/flask 300-350 RPM
931141 500mL Ultra Yield™ Flasks 50/case — Sterile 899424 125-200mL/flask 300-350 RPM
931136-B 2.5L Ultra Yield™ Flasks 6/case — Sterile 899425 500mL (optimum) 300-400 RPM
931136-VC 2.5L Ultra Yield™ Flask w/Vent Cap 6/case — Sterile 899425 500mL 300-400 RPM
Has anyone tested the Ultra Yield™ Flasks for acetate concentration? Can you use it as a starter culture for vaccines?
GSK has kindly provided data on pH, OD, and acetate on their use before vaccines. Acetate seems to gain with normal shake flasks, whereas pH and acetate both stay consistent with Ultra Yield™ Flasks. The flasks actually have shown that they reduce content over time.
What clamps and shakers work best for the Ultra Yield™ flasks?
Ultra Yield™ Flasks are designed to shake in 1 inch orbit shakers. With the higher speeds sticky tape will not work, as higher shaking speeds allow for better aeration. Our 125mL, 250mL and 500mL will work with standard shake flask clamps. The 2.5L can take a standard 2L shake flask clamp, and New Brunswick has a special clamp. Kuhner shakers have also made a special flask clamp. See our clamp cart for specific clamps
What media do we put in the Ultra Yield™ Flasks?
Recommended media is an enriched media with pH balance around 7.4 . TB, EnBase, Magic Media & Plasmid+® are all good examples of highly enriched medias. The pH balance is most useful with buffers that contain phosphate since these are not temperature dependent. Personally, we prefer MOPS at 100 millimolar with any of these medias.
Are the Ultra Yield™ Flasks disposable or re-usable?
The Ultra Yield™ Flasks are priced to be a disposable bioreactor or disposable shake flask. Ultra Yield™ Flasks are reusable, but the cost of the flasks is significantly cheaper than the autoclaving. With labor being around $100.00/per hour it does not make sense to reuse the product? This is why we priced the Ultra Yield™ Flasks at a few dollars. If you were to reuse the flasks we would suggest three times before any drop off in density, as we know plastic can become brittle over time. Some people have used the flasks multiple times, but remember a little detergent in the flasks, and hurting an experiment, is more expensive than just using a new one.
Myths and legends of growing cultures?
  1. LB is a good media to use for my media: Ultra Yield™ Flasks are best when using an enriched media.
  2. Growing cultures for more than 18 hours will damage my culture: What damages the growth and causes anaerobic growth is the insufficient amount of oxygen, and drop in pH when using normal shake Flasks. Ultra Yield™ flasks give sufficient aeration for 7 days of growth at 20°C, and 50 hours at 37°C.
What is missing with LB and minimal media?
LB or minimal media is like feeding someone bread and water. One needs to get roughage, and nutrients and vitamins. This is true with other living organisms as microbes need a balanced diet to grow strong.
Media choices and recommendations for end users?
Different types exist, and by no means is this an endorsement of one over another: Plasmid+®, TB, Magic Media, Enbase, etc.
What systems are people using with Ultra Yield™ Flasks?
People use the shake flasks, on New Brunswick, INFORS HT, Kuhner, and every shaking platform available.

End user Question:

We grow organisms that need to be killed after cultivation by autoclaving. Can the flasks withstand autoclaving for this purpose? Both flasks and seals are sterile and ready to use.
Ultra Yield™ Flasks and AirOtop™ Enhanced Seals come ready to use sterile. As described, people add media, and sterilize the flask with the media in it, but do not use the AirOtopTM Enhanced Seal for this process. Sterilization is best with a piece of Aluminum foil on top. After autoclaving allow the Ultra Yield™ Flasks to cool down before using as they do retain heat. Customers have erred and killed their cells by taking them straight from the autoclave to adding their cells immediately for growth.
How do you grow your cells and media?
We usually prepare a large volume of media and sterilize it in bottles. Then pour the ready-made media into the Ultra Yield™ Flasks, and add the cells. We find this works best, and is easier and faster for multiple runs.

Thomson Instrument Company is not affiliated with TB, Magic Media, Enbase, New Brunswick, INFORS HT, Kuhner, GSK or their products