Following the previous work on nucleic approach to a chemostatic culture of Azotobacter vinelandii (1), unsteady state relevant to a continuous cultivation of the same bacterium was studied especially from a macro-molecular and engineering viewpoint.
Prior to the nucleic approach to this subject, unsteady state realized when batch cultivation is transferred to continuous run by initiating the flow of fresh medium into a single vessel was studied both by experimentation and by calculation using an Analog computer. So far as a marked difference, if any, between experiment and calculation-the latter of which was conducted from a material balance using the value of yield factor secured previously under steady-state condition-does not become problematical, the length of time required before steady state in continuous culture was achieved after initiating the continuous operation could be assessed by the computation.
The nucleic analyses of cells experiencing unsteady state of different nature which was realized by changing the value of dilution rate stepwise from one level to another revealed that the response of cells to a new environment was rather rapid.
Another steady and balanced state of cells was reached, being quite independent of the time when a new level of steady state in terms of cell and substrate concentrations became apparent in an engineering sense of the term. This finding suggests a need of introducing two significant concepts of "biological" and "mechanical" time-lag in handling a transient state due to be associated with a chemostatic culture of micro-organisms.