• Cell inhibition by solvent (interface toxicity) and the loss of interface cells
• Physical defending by depiction of cells to the interface: real coefficients of
distribution in fermenter lesser than in non-cell experiments
• Precipitates transmitted water into the solvent stage
• Problematic control over the whole process
1.2.2.1 In-Stream Recovery
Fermentation and primary separation are accompanied simultaneously but in two
distinct vessels. This means that the fermentation broth is uninterruptedly pumped
through another column containing the selective phase or material which allows a
fraction of the product to be separated, the alcohol-depleted stream is reverted back
to the bioreactor. A typical diagram is shown in Fig. 1.7.
The pros and cons of both modules are definitely among adsorption, liquid-liquid
extraction, stripping and more, depending on the type of separation unit used. The
integrated product recovery techniques of the aqueous broth alcohols may be based
Fig. 1.6 Fermentation in situ recovery process
Substrate
Alcohol partially
depleted
FERMENTOR
IN STREAM
RECOVERY
Alcohol partially
enriched
Fig. 1.7 Fermentation in-stream recovery
1 Downstream Processing of Biofuels
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