yes the yeast require no oxygen to ferment. they are faculative anaerobes in that they can use oxygen to perform celluarl respiration and in the lack of, they use fermentation following a glycolysis process. The use of fermentation clears the pyruvic acid production during glycolysis and allows ATP to be formed althouh it varies from 2-6ATP per process and up to 32ATP for aerobic respiration. From the numbers alone, if oxygen is available there will be no CO2 that is formed except during the krebs cycle where it is extremely minimal