Abstract: A bioreactor valve island is provided according to an embodiment of the invention. The bioreactor valve island includes a sparge mixing region that receives and mixes a first air input and one or more first gas inputs and an overlay mixing region that receives and mixes a second air input and one or more second gas inputs. The bioreactor valve island further includes one or more output valve pairs. An output valve pair of the one or more output valve pairs receives a gas from a gas supply of one or more corresponding gas supplies and selectively outputs both a first gas input of the gas to the sparge mixing region and a second gas input of the gas to the overlay mixing region.