Apparatus and associated methods relate to an optimizable cellular growth chamber, where growth conditions are optimized by adjusting gas pressures through a gas permeable membrane. In an illustrative example, an apparatus may provide a volume to contain growth medium and the cells under propagation, where the volume has limited but non-zero pneumatic communication with a pressure-controlled chamber via a gas-permeable membrane. Associated apparatus and methods are proposed to manage desired growth conditions via deliberate control of parameters, such as partial pressures, for example.