Bubblers / In-Vial Aeration

Overview

An in-vial aerator, which can be hooked up to a gas stream of your choice. Normal stir bar-based mixing in the eVOLVER does not provide enough gas exchange in many situations. These bubblers produce small bubbles that greatly increase gas exchange.

Considerations

Variability Between Bubblers

The assumption is that there will be variability between the bubblers that you make -- even though you will screen them before putting them in a vial cap! This is compensated for by bubbling much more than we need for a given microbe's gas consumption needs. Worse bubblers will not be a problem if the worst bubbler you have provides more than enough gas exchange.

Biofilming

Aerators are great substrates for biofilming. If your strain biofilms, make sure you swap in new bubblers when bubbles noticeably diminish. See Cleaning Protocol.

Because of biofilming, it is useful to have another set of caps/bubblers that can be swapped in without interrupting your experiment. Ideally, you would pre-autoclave these and keep them sterile in aluminum foil. Pause the experiment, check if the vials need to be changed because of biofilm and swap sterile caps and/or vials in.

Media Type Affects Bubble Size

Bubblers will produce different sized bubbles depending on media type. This is related to the amount of salts, proteins, carbohydrates, etc that are in the media. These can act as surfactants to create smaller bubbles. Therefore, largest bubbles will be in water and smallest bubbles will be in rich media, as can be seen below:

<Add picture of bubbler in water vs algae media vs LB>