Aspects of this disclosure relate to liquid-based workflows for strain engineering. In strain engineering, cells undergo a modification process to acquire a desired change or changes in the cells. Some of the cells accept the change or changes and some do not. Provided herein are liquid-based methods for selecting the population of cells that have accepted the change or changes. Also provided herein are liquid-based methods for removing markers from transformed cells and liquid-based methods for isolating clonally pure populations of cells.