Figure 4. Growth chamber of the Evolugator.

a) The growing culture is shown on the right, and is completely contained within a tube clamped at regular intervals to limit unintentional mixing. The density of the culture is measured with a turbidity meter connected to a controller that dynamically regulates the in-flux of new medium. Air bubbles are included at regular intervals to increase the oxygenation level of the medium. b) Upon reaching high density, the right clamp closes, the tubing moves along the track, and the next clamp opens allowing for contact between the growing culture and the fresh medium. c) The fresh medium mixes with the growing culture through diffusion, and the culture resumes growing. d) After sufficient time, the culture again reaches high density. The middle clamp then closes, the tubing shifts on the track once again, the next clamp opens and the new medium is allowed in. This cycle is then continued for the duration of the experiment.