Self-Cycling fermentation (SCF) is a relatively recently developed technique for culturing microorganisms. SCF is a form of sequential batch fermentation, in which batch transfer occurs when the state of the system reaches a predefined threshold, called a decanting criterion. In this talk, we will discuss how to model the microbial dynamics in this process when there are one, two, or more limiting nutrients. Under some restrictive assumptions on the decanting criteria, we are able to completely characterize the dynamics of the system. We also discuss an optimization problem associated with the single nutrient system and compare with the same problem in the chemostat.