How to Efficiently Shake Viscous Culture Broths Culture Broth Viscosity Evaluated in Shake Flasks Studies

Culture Broth Viscosity Evaluated in Shake Flasks Studies In biotechnology, the use of shake flasks is widespread due to their easy handling, especially in process design and optimization as well as in small-scale upstream processing and inoculum production. Recently, geometrically optimized Thomson Optimum Growth® shake flasks were introduced to the market, promoting higher yields with the same shaker footprint. Knowledge on different engineering parameters (including the oxygen mass transfer coefficient, the mixing time, or the power consumption) is essential to compare these new flasks with established shake flasks and to evaluate potential benefits. In the present work, the oxygen mass transfer in Thomson Optimum Growth disposable shake flasks is quantified at 500 mL and 5 L using the PreSens Shake Flask Reader. Erlenmeyer and Fernbach shake flasks are still the predominant shapes, despite their limitations (e.g. the relatively low filling volumes). Consequently, Thomson Instruments developed a new shake flask design: Optimum Growth for cell cultures, allowing filling volumes of up to 60% of the nominal volume. The Shake Flask Reader is built to measure the dissolved oxygen concentration and the pH value in shake flasks by means of single-use sensor spots that are attached to the inner surface of the shake flask. Besides a reduced contamination risk, another decisive advantage of the sensor spots (compared to conventional oxygen probes) is their small size, which does not change the flow behavior. The device can accommodate and measure up to nine shakes flasks (from 125-2,000 mL) simultaneously. The data is transmitted to a PC via a Bluetooth connection.