Products, Intermediates and Effectors

The product is almost the only reason why a bioprocess is run. The main concern is in maximizing the profit which depends directly on the concentration and/or volumetric productivity and/or of the purity of the product. It is therefore interesting to know the values which require measurement. The classical methods to determine product concentrations are typically off-line laboratory methods and the above statements for substrate determinations are valid here, too. 

One may need to account for labile intermediates as found, for instance, in penicillin production [196,304]. Then, on-line analyses will best avoid artifacts due to storage of materials even though the samples are cooled to 4 or 5 °C. 

In summary, bioprocess science needs more quantitative measurements. It is insufficient to know that something happens, we need to know why and how [260]. 

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