INHIBITORY NUTRIENTS
# Analysis of growth rate expressions

## Overview:

Growth rate is fundamental to all bioprocessing with living cells. A key concept is
**growth-limiting nutrient**, the one in
lowest proportion to the others. It will be exhausted first
and is the focus for growth rate control. When limitation can shift from one nutrient to
another, the equations relating specific growth rate coefficient become more complicated. If
one nutrient is inhibitory to growth as its concentration rises, additional terms are needed in
these equations.

## Introduction:

Natural nutrients are seldom pure. Compounds or mixtures of compounds contain carbon,
hydrogen, nitrogen, and other elements in various proportions and may supply precursors at
several locations in metabolic pathways. Very seldom is an unreacted element taken up by
cells; they prefer pre-formed groups. A rigorous treatment of growth rate control should consider
the exact biochemical compositions of all nutrients, but this is impractical. We simplify the
complicated patterns of nutrition by speaking of the "carbonaceous ingredient", the "nitrogeneous
ingredient", and the like.
Select any of the following:

## Reference:

H. R. Bungay, "Growth rate expressions for two substrates one of which is inhibitory", Jour. Biotechnol. 34: 97-100 (1994)

` Last update: 10-Oct-94
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