The effects of self-forcing simple limit-cycle type self-sustained oscillations (SSO) on a single chemostat with the aim to enhance its productivity was investigated using four different microbial systems with increasing complexities. It was demonstrated via simulation that for a chemostat with monod-type growth and with substrate-and-product-inhibited growth and product formation, it is possible to increase its productivity several fold by self-forcing the chemostat with SSO without incurring extra costs normally associated with external periodic forcing. Despite significant difference in the models used to simulate the chemostats, all four systems show a similar pattern of behavior in their productivity-vs.-mean residence time plots.