Ultra Yield Flasks are simple disposable bioreactors that take the place of traditional shake flasks an example would be the Corning® disposable baffled Erlenmeyer flasks (from Corning® Life Sciences). The Ultra Yield Flasks can increase the yield of your microbes by up to 610% when paired with an enriched media and proper growth conditions. The Ultra Yield Flasks offer a low carbon footprint to reusing traditional shake flasks. The Ultra Yield Flasks offer better aeration and mixing qualities that are unique to its design thus enabling the superior growth not found in other flasks such as Corning disposable baffled Erlenmeyer flasks (from Corning® Life Sciences) . An enriched medium allows for increased cell growth in Corning disposable baffled Erlenmeyer flasks (from Corning® Life Sciences) when compared with LB medium in the same flask type. However, the Ultra Yield flasks provide for substantial increases in cell densities when cultures are grown in TB medium compared with similar cultures grown in Corning® disposable baffled Erlenmeyer flasks. The average cell culture densities generated in the Corning® disposable baffled Erlenmeyer flasks following overnight expression using either LB or TB media were, respectively, 2.7 (range 1.9-3.8) and 4.0 (range 2.2-6.4), whereas the average cell density in the Ultra Yield flask with TB medium was 14.0 (range 7.6-20.2). Thus, and average increase in cell density per unit volume of approximately 3.5 is obtained by using the Ultra Yield flask in place of the Corning® disposable baffled Erlenmeyer flasks. The use of the Ultra Yield Flasks now provides additional advantages for high density E. coli fermentation by reducing the experimental footprint 4-fold via its 1L capacity and by virtue of its validation as a scale-up platform. The Ultra Yield Flask is convenient to use, is inexpensive and disposable, and avoids the requirement to pool multiple smaller scale fermentations into a single paste. No other flask available today offers the stand-alone performance of the Thomson Ultra Yield Flask. It is currently being used in the field today by many of our customers in place of a fermentor. Thomson Instrument Company together with users at Genentech, GSK, and Pfizer has validated the Ultra Yield Flask as a suitable system to achieve high-density cell fermentation. It is a disposable bioreactor.