Why is it desirable to couple chemical production to growth?
Why is it desirable to couple chemical production to growth?


When designing new metabolic pathways for chemical production, one has to keep in mind that the purpose of it is to get scaled up (i.e. to reach industrial size).

From the industrial point of view, the faster/simpler a process is, the better. Growth coupled chemical production means that only one step is necessary in order to produce the desired product (before downstream processes). Otherwise, one would have to produce the biomass first (growth step) and then to proceed to the chemical production step. One step is cheaper and faster than two, not mentioning the intermediary steps that could be necessary (cells washing, centrifugation, filtration ...).

The main drawback of growth coupled chemical production is that the final yield ($mol_{final~product}/mol_{substrate}$) is hindered by biomass production. This can be a real issue if the substrate is expensive.