within either a monoculture or a set of mixed-microbial organisms can also be dependent on overall nutrient limitation, not just macro elements. This is especially the case in the 'feast/famine' cycle method for induction of PHA production, wherein carbon is periodically added and depleted to cause famine, which encourages cells to produce PHA during 'feast' as a storage method for periods of famine.

Polyesters are deposited in the form of highly refractive granules in the cells. Depending upon the microorganism and the cultivation conditions,