When the yeast enter fermentation from lack of oxygen, they take the glucose (which they get from the table sugar sucrose), and through some biochemical juggling turn it into 2 molecules of CO2 and 2 molecules of Ethanol (alcohol).
When O2 is present, the sugar is turned into, hmmmmmmmmm, I can't remember....

. But it then enters the citric acid cycle where al lthat carbon is used to create biomolecules. Things like fattyacids, proteins, engine blocks, whatever. The point is that very little of the actual carbon (the table sugar you add) actually ends up as CO2.
You will get less CO2 production when oxygen is present.
Here is a situation you may be familiar with: When you set up a CO2 yeast bottle, there is a lag of several hours before bubbles appear. That lag is the yeast growing in the presence of the oxygen in the liquid. No gas is being produced, (except for very very (meaning no bubbles) small quantities that a carbon eating life form would respire).
Visible CO2 production doesn't occur until the oxygen runs out.
I hypothizize that your bioreactor would stop working or slow down for awhile after adding Oxygen, and I also hypothizize that I need a dictionary.