Introduction of nutrient medium into a fermenter

A method for the continuous fermentation of a culture comprising a nutrient medium, one of the constituents of which is a growth limiting nutrient, and microorganisms capable of utilizing the medium for growth wherein the growth limiting nutrient is supplied to the culture in an amount which corresponds stoichiometrically with the locally available supply of oxygen at an average of at least one position per cubic meter of the effective volume of a fermenter in which the fermentation is performed, said effective volume being the volume in which, through mass transfer from gas bubbles, a positive dissolved partial pressure of oxygen can be maintained, whereby substantially all the limiting nutrient supplied at each position is consumed by the microorganisms present in the culture in the vicinity of that position before oxygen nutrient available to them in the culture in the vicinity of that position is exhausted and becomes the limiting nutrient.