Turbidostat

A turbidostat is a continuous culture device, similar to a chemostat or an auxostat, which has feedback between the turbidity of the culture vessel and the dilution rate. The theoretical relationship between growth in a chemostat and growth in a turbidostat is somewhat complex, in part because it is similar. A chemostat technically has a fixed volume and flow rate - thus a fixed dilution rate. When the cells are uniform and at equilibrium, operation of a chemostat and turbidostat should be identical. It is only when classical chemostat assumptions are violated (for instance, out of equilibrium; or the cells are mutating) that a turbidostat is functionally different. One case may be while cells are growing at their maximum growth rate, in which case it is difficult to set a chemostat to the appropriate constant dilution rate .

While most turbidostats use a spectrophotometer/turbidometer to measure the optical density for control purposes, there exist other options, such as electrical conductivity.