S17: Novel agitation-aeration-hybrid culture vessel construct featuring integrated real time oxygen uptake reporting

One well known drawback of shake flask (often conical Erlenmeyer flasks) culture is its limited atmospheric gas exchange or ventilation.  This may result in reduced cell growth and growth rate due to oxygen starvation and/or carbon dioxide inhibition.  However, forced air sparging using pressurized line gas is not easily workable on smaller size reaction vessel like a shake flask without compromising its advantage in simplicity and economy in time, material, acquisition, and numbers.  Hence, providing realistic up-scale stirring, gas-liquid mixing and headspace air-conditioning in mini or micro scale reaction vessel in numbers, like flasks, bottles, beakers, test tubes, etc., is still a challenge.  Thru in situ impeller pumping, the new stir-and-vent hybrid vessel assembly (US Patent 8,162,295) allows steady fresh gas flow from ambient through a gas intake compartment and then into the reaction mix before returning to ambient thru a gas venting compartment without an external pressure means.  A gas vent riser tube and a gas intake downer tube are two variations of the new assembly.  Current study would quantify the stirrer-induced air mass flow as function of vessel size, working volume, stirrer speed, riser tube diameter and positioning.  With an off-gas oxygen sensor mounted at the riser tube outlet, this novel flask-fermentor hybrid becomes an unique oxygen uptake reporting fermentor suitable for real time fermentation monitoring and high throughput design-of-experiment (DOE) tank-farm use.  Duran GLS80 wide-mouth bottles of 250, 500 and 1,000mL size are used in this study.

REFERENCES

1. Duen-Gang Mou, Industrial Biotechnology, 6(2):100-103, 2010