INULIN ENRICHMENT BY FERMENTATION IN A FLOCCULATING YEAST REACTOR

Simultaneous production of ethanol and fructose enriched syrups was ob tained from Jerusalem artichoke extract using a Saccharomyces diastati cus flocculating yeast in a continuous gas-lift reactor with internal biomass recycle. This allowed the production of 42 g/L of ethanol and 70 g/L of inulin containing up to 92% fructose (fructose/glucose ratio of 11) These results can be compared to the batch and chemostat ferme ntations which gave a higher ethanol concentration but a lower fructos e enrichment. Mass transfert limitations can explain both the producti vity decrease and the selectivity improvement in the gas-lift reactor.