We report the development of a droplet-based microfluidic device, which enables long term culturing of microorganisms inside water in oil microdroplets under semi-continuous conditions. Firstly, a microdroplet containing yeast cells is trapped on chip. After an initial incubation phase, this cell laden droplet is coalesced with smaller nutrient droplets to enable cultivation and time-lapsing under semi-continuous conditions. We demonstrate a proof-of-principle study on a sequential batch experiment, which lays a sound foundation for screening of microorganisms under semi-continuous conditions.