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Continuous fermentation with product recovery by in‐situ extraction
Author(s) -
Weilnhammer Christian,
Blass Eckhart
Publication year - 1994
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270170602
Subject(s) - oleyl alcohol , fermentation , industrial fermentation , extraction (chemistry) , chemistry , chromatography , yield (engineering) , product inhibition , volumetric flow rate , solvent , alcohol , materials science , food science , biochemistry , non competitive inhibition , physics , quantum mechanics , metallurgy , enzyme
The productivity of fermentations is often limited by end product inhibition. This can be avoided by continuous removal of the inhibiting product from the broth. Such in‐situ separation can be conveniently accomplished by liquid‐liquid extraction. As an example, the continuous fermentation of ethanol by the thermophilic, anaerobic bacterium Clostridium thermohydrosulfuricum is investigated in a 20‐1 fermenter with simultaneous in‐situ extraction by oleyl alcohol as organic solvent. Continuous fermentations with and without in‐situextraction were carried out with systematic variation of the independent operating conditions, viz. feed glucose concentration, broth flow rate and solvent flow rate. The experimental results of 18 steady states are reported. They show that in‐situ extractions doubles the yield, selectivity and space‐time yield of ethanol in comparison to fermentations without in‐situ extraction. A biomodel elucidates the influence of feed glucose concentration, broth flow rate and solvent flow rate on the productivity of the fermentation process. Finally, a cost model was developed for the investigated fermentation which allows economic evaluation of the results of experiments and simulation. A sensitivity study elucidates the economic limits and advantages of fermentation with in‐situ extraction compared to a common fermentation without product separation.