EFFECTS OF AIR CURRENTS ON GAS EXCHANGE OF CULTURE VESSELS

In order to investigate the effects of air currents around the culture vessel on gas exchange of the vessel, numbers of air changes of culture vessels were measured under various air current conditions, using carbon dioxide gas as a tracer. Erlenmeyer glass flasks (volume: 400 mL) and polypropylene (PP) caps were used as vessels and vessel stoppers respectively, and three configurations were tested: PP cap only, PP cap with cotton filter around the flask's rim, and PP cap with teflon membrane filter at its top surface. The number of air changes, for each combination of culture vessel and cap, changed according to the air current environment around the vessel. The degree of change of the number of air changes in relation to air current velocity depended on the cap configurations.