Fig. 3
(This figure was modified from Jeong et al. [112])
Adaptive laboratory evolution (ALE) can be performed in the laboratory using three broad approaches. A Serial transfer can be performed in shake flasks with liquid medium where nutrients will not be limited, and an aliquot of the culture is transferred to a new flask with fresh medium for an additional round of growth at regular intervals. B Colony transfer is similar to serial transfer, but is performed on plates with solid medium. C A chemostat comprises a culture vessel in which the population grows under continuous agitation and aeration. Fresh medium is added into the vessel at a defined rate and culture broth is harvested continuously during the process. The figures a, b, and c illustrate the number of cells that grew during ALE the processes shown in A, B, and C, respectively